46 CFR § 11.428 is the most straightforward path to become a Master 100 GRT Near Coastal. You only need 720 sea days in the deck department, with 360 of them on Near Coastal or Ocean Waters.

Most 100 ton courses include Master 100 GRT Near Coastal as one of the USCG Licenses you can obtain. Most USCG Approved Courses can only be used once and only for one USCG License.
If you are thinking about taking a Master 100 ton USCG Approved Course and have 720 sea days in the deck department, with 360 of them on Near Coastal or Ocean Waters we highly recommend getting your Master 100 GRT Near Coastal under 46 CFR § 11.428
If you have 180 days on vessels 51 GRT or larger OR 360 days on vessels 34 GRT or larger you qualify for a 100 ton.
If you have 180 days on vessels 26 GRT or larger OR 360 days on vessels 17 GRT or larger you qualify for a 50 ton.
No worries! Tonnage limitations will apply if you are on smaller boats. This also makes sense as you will probably be working on smaller boats anyway. We recommend not worrying about them and just focus on getting the right type of license for what you currently want to do.
Tonnage limitations are really simple and easy to remove with just 90 sea days once you hold your new MMC! For a mate and a master under 200 GRT all you need is sea time while holding your license to remove them. Here's a blog post that goes into detail.

We hope this made your life a little easier and if you have other questions the MM-SEAS team is always here to help!
MM-SEAS is free to use on your own and if you need some more personalized help you can upgrade to MM-SEAS Expert Access inside of the site.
No matter what, when you are ready to submit your application you can do it yourself, or you can hand the whole thing to us. An MM-SEAS Navita Navigator walks you through submitting in Navita, the Coast Guard's new submission portal, on a short video call. No computer, or not up for a video call? Our team gets your application submitted to the Coast Guard for you anyway. A Stress-Free MMC is $399. Two MM-SEAS licensing experts check every page, we pay your Coast Guard fees at submission and charge your card so you never touch pay.gov, and we stay on it with the National Maritime Center until your credential is issued.
MM-SEAS Expert Access is $99 a year. It is your personal guidance counselor for USCG licensing: what training you need next, which sea time counts, and how to reach the credential you want, by phone, email, chat or a 1 on 1 video call. Expert Access members also get $50 off a Stress-Free MMC.
Nate Gilman is President and Co-Founder of MM-SEAS. He hawsepiped from the deck to a 3rd Mate Unlimited license with full STCW compliance over more than 15 years at sea, and is a veteran of the NOAA Commissioned Corps. He works directly with the National Maritime Center, USCG-approved training schools, and vessel operators on credentialing policy, and writes on sea service documentation, evaluation standards, and how mariners move up the license ladder.