USCG counts up the 360 sea days from the day your application is submitted back 5 years.
The USCG will count back 5 years from the day your application is submitted to the Coast Guard.

As an example if your application is submitted on January 04, 2023 you would get credit for all of the sea days since January 04, 2018. This is unrelated to your MMC expiration date and is solely dependant on when your application is submitted to the USCG.
To determine if you need to take courses to renew your license you need to first Count up how many creditable sea days you have in the last 5 years. (MM-SEAS does this automatically for you).
If you're working on your USCG license renewal, we have everything you need to succeed. Explore our tailored guides for renewing your Six-Pack license, 25 Ton license, 50 Ton license, or 100 Ton Captain license. Start with the Ultimate USCG License Renewal Checklist for a complete overview and ensure a stress-free renewal process.

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.