Lonely Planet review
This lagoon (it shares the same ecosystem as Los Haitises south of Península de Samaná) at the northern end of Calle Duarte was once Río San Juan’s claim to fame, drawing tourists from near and far for boat rides through its tangled mangrove channels. Unfortunately, overuse and pollution mean the lagoon is no longer pristine and swimming is no longer recommended. It’s still fairly picturesque and a dozen or more boatmen still offer tours , which typically cost US$35 for up to seven people and last around an hour, with visits to the mangrove forests, some interesting rock formations and a cave populated by hundreds of swallows. Look for a small shack next to the public bathrooms down by the Laguna – you’ll find it easier to join a group on weekends, when Dominicans come to take this trip.
You can also visit the lagoon on foot – there’s a path on the far side of the Hotel Bahía Blanca along the water’s edge into the mangroves.