Think about St Thomas and ferry..
When planning our trip, I consider both options.
When the price difference between flying directly into EIS vs the ferry drops below $200,
I start looking at the SJU-IES option. Jet Blue out of DCA managed to do this last year.
Right now, the (IAD/DCA)-SJU-EIS option for end of April 2023 is $300 pp more than IAD-STT (Ferry) option.
It's the ferry for us.
