Is there Phone and Internet Service in the San Blas Islands?
Most islands of the San Blas do have Internet. International roaming is available but can be expensive.if your carrier is from the USA.
Instead of using your roaming services that, depending on your local carrier back home, can be expensive, buy yourself a cheap TIgo sim card in any convenient store in Panama city prior to arriving to the catamaran. Top up your new Tigo sim card with credit obtained right there at the store and you are set up.
Some islands and cays do have full internet, others either don’t or have limited access due to poor local antenna reach.