M Street Beach
South Boston, MA
M Street Beach sits between Carson Beach and Pleasure Bay, part of the same DCR corridor along Day Boulevard in South Boston. Lifeguards are posted here in summer, and the beach has a bathhouse, a playground behind the sand, and views across Dorchester Bay to the harbor islands.
Free, easy, and less mobbed than Castle Island, it is what South Boston locals actually use; the weekend crowds and the occasional bacteria advisory are the catch.
How we score beachesBring a chair and skip the crowded Castle Island end. M Street usually has more room to spread out, and you can walk to Pleasure Bay from here in about ten minutes.
Free parking on Day Boulevard and in the nearby lots. Weekend afternoons fill up, so go earlier in the day.
A paved walkway runs along the beach, with easy access to the sand from the sidewalk. The bathhouse is a short walk from the water.
Leashed dogs are allowed year round outside the lifeguarded swim beaches, which are off limits to dogs from Memorial Day through Labor Day.
Lifeguards are on duty on summer days. Water temperatures top out in the upper 60s and low 70s in August, typical for Boston Harbor.
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