Deer Island is a beautiful 2.6-mile island which gives you and your pup the perfect place for a great walk and some outdoor activities. The park includes a walking and jogging path, plus fishing, picnicking, and a great view of the ocean and of downtown Boston. Before Deer Island became a National Recreation Area, it was once a prison for the greater Massachusetts area, meaning there is history to explore here with the flora and fauna. Make sure to bring water with you while you and your pup explore this cool island off the peninsula of Winthrop. After checking out Deer Island, head over to Coughlin Park, another pawsome park off the coast. The park is fenced in and has a playground, benches, sports fields and a picnic area. If Fido isn't a fan of loud sounds, this may not be the park for him since a lot of planes fly overhead to land at the airport.