Can get shuttles right outside the cruise port for $1.20 each way. Booked the Jolly Pirates cruise online for $98 for 4 of us. Snorkelled at 2 reefs and a shipwreck, had unlimited rum punch and drinks.
We have been to Grenada several times and have done the wonderful spice tours. This time just went to Grand Anse beach. Took the water taxi there which cost $16 for 4 of us. Took regular taxi back for $15. Very nice beach. No snorkelling.
Old town was very interesting. People very pushy. Went to Boca Chica which was not worth the money to get there. No snorkelling or even nice swimming. Vendors swarming all over you that will not take "no, thank you" seriously. The fruit man even cheated us!