No. If you arrive on a private yacht from a foreign port, your ESTA does not cover you, whatever your nationality. You need an actual visa, in practice a B-1/B-2.
This catches out a lot of British, Irish, EU, Australian and New Zealand crew, because ESTA works perfectly well when they fly.
Why
The Visa Waiver Program only applies when you travel on an approved "signatory carrier", meaning an airline or shipping line that holds an agreement with the US Department of Homeland Security. The US State Department puts it plainly: you "need to apply for a visa if you will be traveling on a private aircraft or other non-VWP approved air or sea carrier".
A private yacht has no such agreement. Fly into St Thomas and your ESTA is fine, because the airline is a signatory carrier. Arrive on the boat and the same document fails.
This applies identically to the US Virgin Islands, which are legally the United States.
The one exception
If you have already been admitted under the Visa Waiver Program and you sail to an adjacent island (the BVI counts) and return within your original 90 days, you can be readmitted without a signatory carrier. What you cannot do is make your first US entry by yacht on an ESTA.
Note that the 90 day clock does not appear to restart when you come back, so do not plan a long season around island hops.
Sources
Last reviewed 16 August 2026. This is not immigration advice, and US policy changes. Check with your nearest US embassy.