If you snorkel, Dog Islands you will find a great variety of tropical fish in the shallow warm waters. This is not the case for the main villages that have their latrines where land and water. such that boat transport often is required.
Many of the tiny islands with beautiful beaches have one member of the Kuna tribe on the island who collects $1 per person for use of the island for sunbathing or swimming. Be sure to bring small change with you and be prepared to be in the middle of nothing.