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United States · Captain’s license

100 ton captain’s license: Master endorsements explained

A Master endorsement of less than 100 GRT lets you command inspected vessels, so you can carry more than six passengers when the boat’s inspection allows it. Near-coastal Master needs 2 years of service in the deck department, and Great Lakes and inland Master needs 1 year. Whether you end up with a 100 ton captain license, or 25 or 50 tons, depends on the size of the boats you served on.

  • 2 yearsDeck service for near-coastal Master
  • 1 yearService for Great Lakes or inland Master
  • 25, 50 or 100Tonnage limits on a Master under 100 gross tons
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Updated October 2026 · Written from official sources, listed at the bottom of this page

What does a 100 ton captain license require?

RouteSea serviceNotes
Near-coastal2 years in the deck department of a self-propelled vessel on ocean or near-coastal watersGreat Lakes and inland service can stand in for up to 1 year
Great Lakes and inland1 year in the deck department of self-propelled, sail or auxiliary sail vessels3 months on the Great Lakes, or the endorsement is inland only
Inland1 year of service on any watersValid on inland waters, not the Great Lakes

The minimum age is 19 for Master of near-coastal, Great Lakes and inland, or river vessels of 25 to 200 GRT. You don’t need to hold an OUPV first.

Medical, drug test and TWIC →

How your tonnage limit is set

The Coast Guard issues Master and Mate endorsements under 200 GRT at 25, 50, 100 or 200 GRT. Your limit is the larger of two figures: the biggest tonnage on which you did at least 25 percent of your required service, or 150 percent of the biggest tonnage on which you did at least 50 percent. A figure in between rounds up to the next level.

If more than 75 percent of your service was on vessels of 5 GRT or less, the endorsement is limited to vessels of less than 25 GRT.

Raising your tonnage later

  • 90 more days on deck of a vessel in the highest tonnage your Master endorsement allows
  • Enough extra service that, added to your earlier service, the 25 and 50 percent formula gives a higher limit
  • 6 more months in the deck department on vessels in your highest tonnage, which raises the limit one step

To raise an inland Master above 100 GRT, or to get a Mate endorsement of 100 GRT or more, you also complete extra exam topics listed in Subpart I of 46 CFR Part 11.

Sailing endorsement

To command sail or auxiliary sail vessels, you add sail service on top of the main requirement: 12 months on sail vessels for near-coastal Master of less than 100 GRT, and 6 months for Great Lakes and inland or inland Master. That time can come from before your Master endorsement was issued.

Mate, 200 ton and bigger yachts

Mate of near-coastal vessels of less than 200 GRT needs 12 months of deck service. A near-coastal OUPV holder can get it by passing an exam on the rules and regulations for small passenger vessels. Near-coastal Master of less than 200 GRT needs 2 years of service, 1 year of it as Master, Mate or the equivalent while holding an endorsement such as OUPV, plus an exam.

Exam subjects for Master →Which boats need a Master →
Sources: eCFR and 5 more. Checked October 2026.

Rules and fees can change, so check the official site before your test.

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