We snorkeled at Palamino island (took a boat from Fajardo).
We also loved this area, just past Isla Verde. It’s mostly locals. Drive to the part where you see an ocean “pool” .
It’s only 2-3 ft deep but good visibility for snorkeling. You can and should stop to eat at one of the roadside shacks in Pinones while there!
https://www.tripadvisor.com/Attraction_Review-g644389-d12340087-Reviews-Playa_La_Pocita_De_Pinones-Carolina_Puerto_Rico.html