The book is narrated in the first person by the author, who is referred to as ‘J’ by his friends. It begins with J, and his friends harris and George, deciding to take a boat trip up the Thames from Kingston to oxford, and then back again (the book was written in 1888, when boating on the Thames was enormously popular). They are unanimous in agreeing that this is a good idea (except for J’s dog, Montmorency, who doesn’t care for boating).
They have trouble getting packed, and in the morning Harris and J take a train to Kingston, where the boat is waiting for them. George is joining them later when he has finished his work at the bank. They row up past Hampton Court, where Harris describes an incident when he got lost in Hampton Court maze with some friends (this is one of the funniest parts of the book).
George joins the party, and they have trouble towing the boat, and later they have even more trouble trying to put the cover over the boat for the night. They all get fed up with each other, but cheer up when they have a good Tea. There is a long passage about the signing of Magna Carta (there are several passages like this in the book, where the author gets serious for a bit).
They have various other mishaps as they travel up the river, like the time when they are having tinned pineapple for tea, and can’t find the tin-opener. They spend a lot of time trying to open it with no success. And there are stories of other trips they made up the river, like the time J was ou tin a boat with his cousin, and they thought they were going crazy because they couldn’t find Wallingford Lock (it turns out the lock had been demolished some years earlier). And there ere is the time when they are in an inn which has a stuffed trout in a case on the wall, and several different people come in and claim to have been the one who caught it, but when George stands on a chair to look at it, he knocks it down and it breaks – it turns out to be plaster of Paris!
When they reach Oxford, and start to travel back, it starts to rain, and they aren’t enjoying themselves so much. So they abandon the boat and take the train back to London, where they go to a show and then have a good dinner in a restaurant. They make a toast “Here’s to three men well out of a boat!”