Sea Shepherd volunteers on anti-poaching patrol became stranded late Friday on a small island near the mouth of the Rio Matina, said the Servicio Nacional de Guardacostas.
The coast guard said that a launch rescued the eight volunteers and the four-man crew of their launch that had suffered mechanical trouble.
Sea Shepherd has maintained patrols to prevent the poaching of turtle eggs on the Caribbean coast.
The coast guard said that the rescue was accomplished despite driving rain and heavy currents at the river mouth.
The four crew members of the stricken launch were Costa Rican but the volunteers were Dutch and British, said the coast guard.