USCG Sea Time Requirements for a Captain's License
Sea time is the foundation of every USCG captain's license application. Before you can sit for the exam, you must prove that you have spent enough time underway on qualifying waters. Here is everything you need to know: what counts, how much you need, how to document it, and how to build it faster.
Based on 46 CFR Part 10 and NMC evaluation guidelines. Last reviewed March 2025.
360
days for OUPV
Six-Pack license
90 days near-coastal if near-coastal route
720
days for Master 100 GRT
360 days as Mate or above
360 days near-coastal or ocean
10
year lookback window
No sea time older than 10 years
90 days within last 3 years
What Counts as a “Day” of Sea Service
The USCG definition
One qualifying sea service day equals any calendar day on which you served underway for at least 4 hours on a motorized vessel 26 feet or longer on waters subject to U.S. jurisdiction.
- 1.Only one day credited per calendar day, even if you take multiple trips.
- 2.The 4-hour minimum is underway time, not dock time or anchor time.
- 3.You must be serving as crew or operator, not as a passenger.
- 4.The vessel must be motorized for the base OUPV and Master licenses.
This structure means that a full-time deckhand on a charter fishing boat can earn 150 or more qualifying days in a single peak season. A recreational boater who goes out three or four times per week can easily earn 100 days per season. Even part-time boaters who go out once or twice a week can hit 360 days in three years.
What you cannot do is claim a half-day trip as a full day or claim dock time as underway time. The NMC cross-checks documentation and will flag logbooks that show suspiciously identical hours or implausible trip counts.
The 360-Day Rule: The 10-Year Lookback Window
Critical rule
All qualifying sea service must have been earned within the 10 calendar years immediately preceding your application date. Any sea service older than 10 years is ignored entirely, regardless of how well documented it is.
Many applicants are surprised to learn that sea time expires. If you spent years sailing or boating in your twenties and then took a decade-long break, that old experience does not count. You would need to start building sea time again within the 10-year window before your application date.
On top of the 10-year rule, there is a separate recency requirement: at least 90 days of your qualifying sea service must fall within the 3 years immediately before your application. This is true whether you are applying for OUPV or Master. The recency requirement ensures that your experience is current, not just accumulated long ago.
How the rules interact: an example
Suppose you apply on January 1, 2026:
- - Sea time from 2015 or earlier: does not count (outside 10-year window)
- - Sea time from 2016 to 2022: counts toward your total, but cannot fulfill recency requirement
- - Sea time from 2023, 2024, or 2025: counts toward total AND fulfills the 90-day recency requirement
You need at least 90 days from the 2023-2025 window, plus enough additional days from the full 10-year window to reach your license's total requirement.
OUPV (Six-Pack) Sea Time Requirements
The OUPV license, commonly called the Six-Pack or Captain's Six-Pack, authorizes you to carry up to 6 paying passengers on uninspected vessels. It is the most popular entry-level commercial captain's license.
Inland OUPV
- 360total qualifying days
- 90days on inland waters specifically
- 90days within the last 3 years
- Alldays within the last 10 years
Covers rivers, lakes, bays, harbors, and other protected inland waters
Near-Coastal OUPV
- 360total qualifying days
- 90days on near-coastal or ocean waters
- 90days within the last 3 years
- Alldays within the last 10 years
Covers offshore waters up to 100 miles from the U.S. baseline
What the 90 near-coastal days means in practice
If you're applying for a near-coastal OUPV, 270 of your 360 days can be on any qualifying waters (inland, rivers, lakes, protected bays). But 90 of those days must specifically be on waters beyond the baseline or on open coastal waters. If you only boat on a lake or bay, you may qualify for inland only and would need to add near-coastal time before applying for the near-coastal endorsement.
OUPV age requirement
You must be at least 18 years old to apply for an OUPV license. Sea time earned before age 18 can still count toward your total if it falls within the 10-year window and meets all other requirements.
Master 100 GRT Sea Time Requirements
The Master of Vessels Not More Than 100 Gross Register Tons license allows you to operate passenger vessels carrying more than 6 passengers (inspected vessels). It requires substantially more sea time and a portion of that time must be in a supervisory or officer-level role.
Master 100 GRT requirements breakdown
Total qualifying sea service days
All within the last 10 years, 90+ days in the last 3 years
Days as Mate or above (officer-level service)
Half your sea time must be in a supervisory or command role
Days on near-coastal, ocean, or Great Lakes waters
Required for a near-coastal Master endorsement
Minimum age at application
One year older than the OUPV minimum
What counts as Mate or above?
The NMC considers Mate or above to mean any service as a licensed officer, acting officer, or in a supervisory capacity over other crew. Common examples include:
- - Serving as Master or Captain of any vessel
- - Serving as Mate on a commercial vessel
- - Serving as operator-in-charge on a charter or passenger vessel
- - Holding an OUPV license and operating under it commercially
- - Military service as a commissioned or warrant officer in a nautical capacity
Upgrade path from OUPV to Master
Many mariners get their OUPV first, operate commercially under that license, and use that commercial service time as the “Mate or above” portion of the Master requirement. Operating as an OUPV licensee counts as officer-level service for Master upgrade purposes.
What Vessels Count for Sea Time
Not every boat qualifies. The USCG has specific rules about vessel type, size, propulsion, and documentation status.
Qualifying vessels
- ✓Motorized vessels 26 feet or longer
- ✓USCG-documented vessels (any size meeting other criteria)
- ✓State-registered motorized vessels 26 feet+
- ✓Commercial fishing vessels (as licensed crew)
- ✓Charter boats, dive boats, whale watch vessels
- ✓Ferries and water taxis
- ✓Military vessels (with proper documentation)
- ✓Auxiliary sail vessels with inboard or outboard engine
Non-qualifying vessels
- ✗Vessels under 26 feet (for OUPV/Master base requirement)
- ✗Pure sailboats with no engine (for base OUPV/Master)
- ✗Kayaks, canoes, rowboats, paddleboards
- ✗Personal watercraft (jet skis) regardless of length
- ✗Inflatable vessels without rigid hull
- ✗Time as a passenger on any vessel
- ✗Time at anchor or at dock
- ✗Sea time on foreign-flagged vessels (in most cases)
Documented vs. state-registered vessels
Both USCG-documented vessels and state-registered vessels qualify for sea time credit. Documentation status does not determine eligibility. What matters is that the vessel is motorized, at least 26 feet, and operated on U.S. waters. You should record both the vessel's registration or documentation number in your logbook to verify it if the NMC questions your application.
Sailboats and the sailing endorsement
Pure sail time (no engine) does not count toward the OUPV or Master base license. However, if you want to add a Sailing Endorsement to your OUPV or Master, you need 180 days of sailing vessel service, with 90 of those days as operator. Auxiliary sailboats with engines can count as either motorized or sailing time, depending on how you operated them during that trip.
Crew vs. Passenger: Why the Distinction Matters
Sea time credit requires that you were actively serving in a crew capacity. Being on the water as a passenger does not count, regardless of how long the trip was or how many trips you took. This is one of the most common documentation mistakes applicants make.
Counts as crew service
- ✓Helm watch or navigation duties
- ✓Deck work, line handling, anchoring
- ✓Deckhand on a charter fishing boat
- ✓Operator of your personal vessel
- ✓Watchkeeping duties on overnight passages
- ✓Safety officer or divemaster on a dive boat
Does not count
- ✗Riding as a paying customer on a charter
- ✗Fishing as a passenger on a head boat
- ✗Ferry or water taxi as a commuter
- ✗Cruise ship vacation (any role as guest)
- ✗Being on a friend's boat but not operating or crewing
Gray area: informal crew on private vessels
Many applicants have years of experience as informal crew on friends' or family members' boats. This absolutely counts, but documenting it can be challenging. You will need the vessel owner to complete a CG-719S Sea Service Affidavit attesting to your service. The affidavit must specify your role (not just “was on board”), the vessel details, and approximate dates and hours. Keep a contemporaneous logbook to support the affidavit.
How to Document Sea Time: Step-by-Step
Poor documentation is the single most common reason USCG applications are delayed or rejected. The NMC needs enough information to verify each day of service independently. Here is the complete documentation framework.
Keep a contemporaneous logbook
Start logging every underway trip immediately, even if you are years away from applying. A contemporaneous logbook (written at or near the time of the trip) carries far more weight with the NMC than a reconstructed one written later from memory.
Each entry must include:
- - Date of the trip
- - Vessel name, registration or documentation number, and length
- - Departure and arrival port or location
- - Departure time and arrival time (to establish hours underway)
- - Waters navigated (inland, near-coastal, ocean, Great Lakes)
- - Your role (Captain, Operator, Mate, Deckhand, Crew)
- - Weather conditions if noteworthy
Use the CG-719S Sea Service Form
The CG-719S (officially the “Sea Service Form”) is the standard USCG form for documenting sea service. It must be completed and signed by a person with direct knowledge of your service. Depending on your situation, that is typically your employer, the vessel owner, or the Master of the vessel you served on.
The CG-719S must include:
- - Vessel name and official number or registration number
- - Gross tonnage and vessel type
- - Period of service (from and to dates)
- - Waters navigated (geographic area)
- - Your capacity (position held)
- - Approximate hours per day underway
- - Total days of service claimed
- - Signature of certifying person with their title and contact information
For recreational sea time where you were the owner and operator, you complete the form yourself and add a witness signature. The witness must have personal knowledge of your service and signs under penalty of perjury.
Get employer letters for commercial service
If you worked on a commercial vessel, an employer letter supplements the CG-719S and significantly strengthens your application. The letter should be on company letterhead and signed by an officer of the company.
Employer letter template — include all of these elements:
[Date]
To Whom It May Concern / National Maritime Center:
This letter confirms that [Your Name] was employed by [Company Name] as [Position/Capacity] aboard the vessel [Vessel Name], Official No. [Number], from [Start Date] to [End Date].
During this period, [Your Name] served an average of [X] hours per day underway. The vessel operated on [waters, e.g., near-coastal Gulf of Mexico] and is [length] feet in length and [GRT] gross register tons.
[Your Name]'s capacity during this employment was [describe duties: e.g., Deckhand responsible for safety equipment, line handling, assisting passengers, and maintaining watch under direction of the Master].
Please contact me at [phone/email] with any questions.
Sincerely,
[Name, Title, Company Name, Contact Information]
Document military sea service with official records
Military sea service is documented primarily with your DD-214 (Report of Separation) showing your rate and duties. The NMC will also accept official orders, service records, sea duty certificates, and similar official military documents that establish your sea duty assignments. Military time is typically very strong documentation, but you must specify the vessels, waters, and your duties. Contact the NMC before submitting if you have primarily military service, as evaluation procedures may differ.
Organize and total your documentation before submitting
Before submitting to the NMC, create a summary sheet that totals your sea service by:
- - Total days claimed
- - Days on near-coastal or ocean waters (if applying for near-coastal)
- - Days within the last 3 years (recency requirement)
- - Days as Mate or above (if applying for Master)
- - List of supporting documents attached, with page numbers
This makes the evaluator's job easier and reduces the chance your application is returned for correction.
Sea Time Documentation Checklist
Use this checklist before submitting your NMC application
Logbook entries cover all claimed dates with vessel name, registration number, departure/arrival times, and waters navigated
Each entry shows hours underway meeting the 4-hour minimum
Your role on each trip is clearly stated (not just dates and vessel)
CG-719S completed for each vessel or employer, signed by certifying person
Employer letters obtained for all commercial service (on company letterhead, signed)
Military service documented with DD-214 or official orders
All days fall within the 10-year lookback window
At least 90 days fall within the last 3 years (recency requirement)
Route-specific days are clearly identifiable (near-coastal, ocean, inland)
For Master applicants: officer-level days are separately identified and total at least 360
Summary sheet prepared showing total days by category
All forms signed and dated with no blank required fields
Common Documentation Mistakes That Delay Applications
Claiming days without meeting the 4-hour minimum
A short afternoon cruise that was only 2-3 hours does not qualify. The NMC will question logbook entries with consistently uniform hours that seem inflated. Log actual departure and arrival times.
Logging vessel size incorrectly
Many applicants claim sea time on vessels under 26 feet, which do not count. If you use multiple vessels, make sure each one meets the 26-foot requirement. Include vessel length in every logbook entry.
Failing to identify the route
If you're applying for a near-coastal endorsement, your documentation must show that 90 of your days were on near-coastal waters. A logbook that just says “went fishing” without identifying the body of water leaves the evaluator unable to assign the days to the correct route.
Missing signatures on CG-719S forms
An unsigned or improperly signed CG-719S is rejected outright. The certifying person must sign with their full name, title, and contact information. Electronic signatures are accepted but must be on the actual form.
Submitting a reconstructed logbook without a witness
If you reconstruct sea time from memory, calendar records, or bank statements, you must have a qualified witness complete a CG-719S. A bare logbook reconstructed after the fact and signed only by you carries little weight.
Including time outside the 10-year window
Listing sea service from 11 or 12 years ago wastes everyone's time and can raise questions about your application. Only list days within the last 10 years.
Not separating near-coastal days from inland days
If your logbook mixes inland and near-coastal days without clearly identifying each, the NMC may not be able to give you credit for near-coastal route-specific requirements.
How the NMC Evaluates Your Sea Time
The National Maritime Center is the federal office that processes all merchant mariner credential applications, including captain's licenses. Understanding how they evaluate sea time can help you build a stronger application.
Step 1: Completeness check
The NMC first checks that all required forms are present and complete. Missing signatures, blank fields, or missing forms will result in a deficiency letter asking you to supplement. This is the most common source of delay and can add 4-8 weeks to processing time.
Step 2: Day count and window verification
Evaluators count the days claimed and verify they fall within the 10-year window. They check the recency requirement separately. If your totals are close to the minimum (e.g., you claim exactly 360), the evaluator may scrutinize individual entries more carefully to ensure each qualifies.
Step 3: Route verification
For endorsements requiring route-specific days (near-coastal 90 days for OUPV, or near-coastal 360 days for Master), evaluators verify that enough days are documented as being on qualifying waters. They look at both your logbook entries and the waters identified on your CG-719S forms.
Step 4: Capacity and officer-level verification (Master)
For Master applications, evaluators separately count days served as Mate or above. They look at your stated capacity on each CG-719S and in your logbook. If it is unclear whether you were serving as an operator or deckhand, the days may be counted as deckhand and not credited toward the 360 officer days requirement.
Step 5: Credibility assessment
The NMC may question documentation that appears internally inconsistent, such as a logbook claiming 6 days per week for years on end, or entries that all show exactly 4 hours underway (suggesting the log was created to meet the minimum). Credible documentation has natural variation and specificity.
How to Get Sea Time Fast
If you need to build sea time quickly, there are several strategies that work far faster than recreational boating alone. Here are the most effective approaches, roughly ordered by speed.
Get a deckhand job on a charter or commercial vessel
This is the fastest path by far. A full-time deckhand position on a charter fishing boat, dive boat, water taxi, or whale watch vessel can produce 100-150 qualifying days in a single peak season (April through October in most regions). Many operations hire deckhands with no license required.
Search for “deckhand jobs” at your local marina, fishing pier, or dive shop. Positions often come with tips in addition to wages, and the sea time you earn is commercially documented on the CG-719S, which carries maximum credibility with the NMC.
Join yacht delivery crews
Delivery captains regularly need crew for offshore passages. A single passage from, say, Rhode Island to Florida can yield 7-10 consecutive days of qualifying sea time on near-coastal or ocean waters. Longer deliveries or international deliveries can produce 30 or more days in a single trip.
Join the Cruisers Forum, Sailing Anarchy, or contact local offshore sailing clubs to find delivery opportunities. Deliveries typically cover your travel and living expenses, though pay varies.
Crew on offshore sailboat races
Offshore races such as the Chicago Mac, Annapolis to Newport, Marion Bermuda, Transpac, and local overnight distance races can produce multiple days of near-coastal or ocean sea time in a single event. These races count as qualifying sea service if the vessel is motorized (auxiliary sail with engine).
Contact your local offshore racing fleets and post on crew boards seeking positions. Offshore crews are almost always welcome, especially for longer races.
Volunteer with the USCG Auxiliary
Coast Guard Auxiliary operations, patrols, and support missions conducted on the water can count as qualifying sea service. Contact your nearest Auxiliary Flotilla for information on joining and what types of operations count. Auxiliary service is well-documented and carries strong credibility.
Enroll in a sea education program
Programs like Sea Education Association (SEA Semester), Outward Bound Maritime, or NOAA's Teacher at Sea can produce weeks of qualifying sea time in structured programs. Some maritime academies offer short-term sea term programs open to non-students. These programs produce strong documentation and often include near-coastal or ocean route time.
Commit to consistent personal boating
If you have access to a qualifying vessel, consistent personal boating three to four times per week during the boating season can produce 100-150 days per year. Most people who boat regularly can hit 360 days in two to three seasons without changing their habits much. The key is starting your logbook immediately and logging every trip.
Combining Sea Time from Multiple Vessels
You do not need all your sea time on a single vessel or from a single employer. The NMC accepts and encourages combining sea service from multiple sources, as long as each source is properly documented.
Rules for combining sea time
No double-counting calendar days. If you went out on your personal boat in the morning and worked on a charter boat in the afternoon of the same day, that still counts as one sea service day. You get one day per calendar date, regardless of how many vessels or employers.
Each source must be separately documented. You need separate CG-719S forms (or logbook entries with attestation) for each vessel and each employer. Do not combine multiple vessels into a single form.
Route days must add up across all sources. If you need 90 near-coastal days, those 90 days can come from different vessels and employers, but each day must be on near-coastal waters and documented as such.
Include a summary cover sheet. When combining multiple sources, create a spreadsheet or table showing each source, the date range, total days, route type, and supporting document reference. This makes the evaluator's job easier and reduces deficiency letters.
Example: combining sea time from three sources
| Source | Total Days | Near-Coastal Days | Last 3 Years |
|---|---|---|---|
| Personal boat (recreational, 2019-2025) | 180 | 40 | 60 |
| Charter fishing deckhand (2023 season) | 120 | 120 | 120 |
| Delivery crew (2024, two passages) | 18 | 18 | 18 |
| Total | 318 | 178 | 198 |
This applicant needs 42 more total days to reach 360, but already meets near-coastal (90+ days) and recency (90+ days in last 3 years) requirements. A few more months of recreational boating would qualify them.
Frequently Asked Questions
Does fishing count as sea time?
Yes. Fishing on a qualifying vessel counts if you were the operator or crew member and were underway for at least 4 hours. This includes recreational fishing on your own boat and commercial fishing as crew. Fishing as a passenger on a party boat does not count.
Can I count time working on a vessel that is not yet 26 feet?
No. The 26-foot minimum applies to the vessel, not the waters. A 25-foot vessel operating offshore does not qualify. A 26-foot vessel on an inland lake does qualify, assuming it is motorized and you meet all other requirements.
Does anchoring overnight count as underway time?
No. Anchored time is not underway time. If you motor out to an anchorage, spend the night at anchor, and motor back, only the actual motoring hours count toward the 4-hour daily minimum. Overnight passages where you are actively underway do count.
What if I lost my logbook?
A lost logbook is a serious problem, but not necessarily fatal to your application. You can reconstruct sea service using other documentation: credit card or fuel receipts, marina records, photos with metadata, vessel maintenance logs, or statements from people who witnessed your trips. For each reconstructed period, get a CG-719S signed by a credible witness.
Does sea time from another country count?
Generally, no. The USCG requires sea service on “waters subject to U.S. jurisdiction.” However, some exceptions apply for military service and for certain documented service under foreign flag vessels. Contact the NMC directly to evaluate your specific situation before building your application around foreign sea time.
Can I get sea time credit for working on a houseboat?
A houseboat that is motorized and 26 feet or longer qualifies as a vessel. If you were operating it underway (not just living aboard while docked), and it meets all other criteria, yes. However, be prepared for the NMC to ask questions about how many hours per day the vessel was actually underway rather than stationary.
What if my employer refuses to complete a CG-719S?
If a former employer is out of business or unresponsive, you can use other means: employment records, payroll stubs, port clearance records, or any official documentation that establishes you worked on that vessel. A credible third-party witness (such as another crew member or the vessel owner) can also complete a CG-719S with knowledge of your service. The NMC has procedures for handling undocumented employment.
How far in advance should I start building my sea time log?
Start today, regardless of when you plan to apply. There is no penalty for logging sea time years before you need it. Every trip you fail to log is a day you cannot claim. The easiest sea time to document is time that was logged contemporaneously, not reconstructed from memory.
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This guide is for informational purposes only and is based on 46 CFR Part 10 and NMC evaluation policies as of early 2025. Regulations and NMC procedures can change. Always verify current requirements with the National Maritime Center at www.dco.uscg.mil/nmc or by contacting an NMC-affiliated Regional Examination Center before submitting your application.