Cambridge is under an hour from London King's Cross on the fastest trains, which puts it among the shortest day trips out of the capital. The colleges, the river and the Fitzwilliam Museum all sit within a twenty minute walk of each other, so the day is spent in the city rather than getting to it. It suits anyone who wants architecture and an hour on the water in the same day.
The one thing Cambridge has that Oxford does not is the Backs: a run of college lawns down to the Cam that you can see properly from a punt.
Is it worth a day trip?
Yes. Cambridge is smaller and flatter than Oxford, the sights are closer together, and a single day covers the centre without hurrying. If you only have one day for an English university city and you want to be on the river, choose Cambridge.
The caveat is access. Colleges close to visitors during exam season, usually across late spring, and for events at other times of year. Services can close King's College Chapel without notice, so check on the morning you travel.
Consider staying overnight if you want evensong in King's College Chapel, which is sung in term time and is the single best thing the city does. It falls in the late afternoon, which is exactly when a day tripper is thinking about the train home. For how to judge that trade off, see how far is too far for a day trip.
Getting there
Two separate lines run from London. Trains from King's Cross, operated by Great Northern and Thameslink, are the quicker route, with the fastest services taking a little under an hour and slower ones around an hour and a quarter. Greater Anglia runs from London Liverpool Street via Tottenham Hale and Harlow, usually taking somewhere between an hour and ten and an hour and a half.
Tickets come from either operator or any national rail retailer. Cambridge station is about a twenty five minute walk from King's College, or a short bus or taxi ride if you would rather start with the colleges than the suburbs.
The day, hour by hour
09:30 King's College Chapel. Start with the building everyone comes for. The fan vault is the largest of its kind anywhere, running the full length of the chapel, and Rubens's Adoration of the Magi hangs behind the altar. Entry is ticketed through the college; allow an hour, and stand at the west end for a moment before walking in.
10:30 Trinity College. Five minutes north along Trinity Street, Trinity has the largest court in Cambridge and the Wren Library beyond it, which holds Newton's own copy of the Principia and A A Milne's Winnie the Pooh manuscripts. The library has limited opening hours, so check them before you arrive rather than after.
11:30 St John's College. Next door again, St John's runs across both banks of the Cam and is joined by the covered Bridge of Sighs, best seen from the river or from the neighbouring Kitchen Bridge. The chapel tower and the red brick Tudor gatehouse are worth the detour through the courts.
12:30 the Backs. The stretch of lawn and meadow behind the river-facing colleges, crossed by footpaths and open to walk. This is the view of Cambridge that appears on postcards, and it costs nothing. Take it slowly, then head back towards Silver Street.
13:30 punting. The Backs are properly seen from the water. You can hire a punt and pole it yourself, which is harder than it looks, or take a chauffeured trip and listen to the commentary instead. Most operators run from Mill Lane by Silver Street Bridge or from Quayside.
15:00 the Mathematical Bridge. The wooden footbridge at Queens' College, built from straight timbers arranged in a curve. The story that Newton designed it and that it once held together without fasteners is untrue. You can see it from Silver Street Bridge without entering the college.
16:00 the Fitzwilliam Museum. A fifteen minute walk south on Trumpington Street, the Fitzwilliam is free and much larger than it appears from the portico. Antiquities on the ground floor, European painting upstairs, and a strong collection of illuminated manuscripts.
17:30 Market Square. The day ends in the open market between Great St Mary's and the Guildhall, trading on the same site for around a thousand years. Stalls wind down in the late afternoon, so this is a stop for the atmosphere, a last look at the tower of Great St Mary's and something to eat before the walk to the station.
What to book ahead
Book King's College Chapel entry for a set time if you are travelling at a weekend or in summer. Chauffeured punt tours are worth reserving in good weather, though self-hire is usually available on the day. Trinity and the Wren Library cannot be booked, so check their hours instead.
Open this day trip in Tralendr
All eight stops are saved in order with their times, and each one is pinned on a map, which makes the geography of the colleges along the river obvious at a glance.
Open the Cambridge day trip plan. It opens on a map without an account and is yours to change: move punting to the morning when the river is quieter, add Kettle's Yard, or build the whole afternoon around evensong instead of the museum. Share the link and whoever is coming sees the same plan.
The Oxford day trip from London is the other side of that comparison. More routes are in all our day trips, and the approach behind them is in how to plan a day trip.