actually cheaper...for 4 people and i didn't choose the cheapest fare as I want to pick my seats...DCA to SJU

Look at Jet blue 1347 down and 1348 back.

https://www.google.com/flights?lite=0#flt=DCA.SJU.2020-05-11*SJU.DCA.2020-05-19;c:USD;e:1;sd:1;t:f

We do charter (Island Birds) because I have 9 and that fills plane. Charter picks up at airport and even though we have sleep aboard 1st night I usually get to base by 1 and am out on the water by 4

I have done Intercaribbean, Seaborne (now Silver), and Cape Air. The advantage of Seaborne/Silver is that it is booked on 1 ticket so they (Jet Blue) have to get you there...the advantage of booking separately is that is much cheaper but you may get stuck

For me living in NOVA STT is a pain and not a direct flight and I have been stuck there many times. SJU has much more choices