Boston Common to Union Square, Somerville

How to get from Boston Common to Union Square, Somerville on public transit, with the stops, times and the last trip of the night.

By Ahmad Haji, founder of Cobblehop · October 30, 2026

Get the live route from Boston Common to Union Square

Step by step

1. From Boston Common, walk about 4 min to Park Street.
2. At Park Street, take a Green Line D train toward Union Square.
3. Ride 6 stops, about 20 min, through Government Center, Haymarket, North Station, Science Park/West End and Lechmere, and get off at Union Square.
4. Walk about 7 min to Union Square, Somerville. Use the Prospect St, Webster Ave exit.

Other ways to go

• Walk about 7 min to Downtown Crossing, then take the Orange Line toward Oak Grove to Sullivan Square, then bus 109 to Somerville Ave @ Union Sq: about 33 min.
• Walk about 4 min to Park Street, then take the Green Line toward Medford/Tufts to Lechmere, then bus 87 to Bow St @ Warren Ave: about 33 min.

Which one is faster depends on when you leave. Cobblehop compares them with live times and gives you the one that gets you there first.

Times and frequency

First and last trip are when the first train of the trip leaves Park Street, on the fall 2026 schedule. "How often" is for Green Line trains to Union Square.

Late at night

On weekdays, the last trip that works leaves Park Street at 1:20 am and gets to Union Square, Somerville around 1:54 am, using Green Line. On Friday nights it runs later: the last trip leaves at 2:18 am. On Saturday nights the last trip leaves at 2:14 am, and on Sunday nights at 1:16 am. Late at night, ask Cobblehop for the last trip. It checks live times and tells you when to leave.

Tips for this trip

• Check the branch letter. B trains and C trains and E trains from Park Street don't go to Union Square.
• Know your stop. Get to the door after Lechmere. The next stop is Union Square. Start a live trip in Cobblehop and it alerts you before your stop.
• Union Square station is the end of the Green Line D branch, a short walk from the square.

Step-free access

MBTA data lists every station on this route (Park Street and Union Square) as accessible. Park Street has 6 elevators in MBTA data. Elevators do break, so check the MBTA's elevator alerts before you go.

What it costs

• Subway. $2.40 one way.
• How to pay. Tap a contactless credit or debit card, phone or watch at the fare gate or bus door, or use a CharlieCard or CharlieTicket.
• Kids. Children 11 and under ride the MBTA free.

Fares as of October 2026. Check the MBTA's fares page before you ride.

Boston Common to Union Square, Somerville: common questions

Related routes

• Boston Common to Inman Square
• Boston Common to Cambridge Hospital
• South Station to Union Square, Somerville
• North Station to Union Square, Somerville
• Never miss your stop (guide)

More routes from Boston Common

• Boston Common to Central Square, Cambridge
• Boston Common to Harvard Art Museums
• Boston Common to Harvard Museum of Natural History
• Boston Common to MIT Museum
• Boston Common to MIT
• All routes from Boston Common

Official sources

Cobblehop is independent and isn't affiliated with these agencies or operators. Schedules on this page come from MBTA/MassDOT public data. Check their pages for the latest schedules and service changes:

• MBTA: Green Line
• MBTA: Park Street station
• MBTA: Union Square station
• MBTA: fares
• MBTA: elevator and accessibility alerts

Published October 30, 2026. Times were computed from the fall 2026 MBTA schedule (2026-11-04 for weekdays). Service changes, so check Cobblehop for live times before you go.