We Didn't Mean to Go to Sea is the seventh book in Arthur Ransome's Swallows and Amazons series of children's books. It was published in 1937. In this book, the Swallows (John, Susan, Titty and Roger Walker) are the only recurring characters. They are staying with their Mother and baby sister Bridget in a new location, Pin Mill on the River Orwell upstream from the ports of Felixstowe and Harwich and are in Suffolk to meet their Father, Navy Commander Ted Walker who is returning overland from a posting in Hong Kong (then a British possession) to take up a new posting at Shotley. (In Swallows and Amazons his ship was at Malta but under orders for Hong Kong (as also stated in Missee Lee).

The book features a small sailing cutter, the Goblin, which is almost identical to Ransome's own boat Nancy Blackett. Ransome sailed Nancy Blackett across to Flushing by the same route as part of his research for the book. The navigational detail and the geography are both correct for the period when the story is set, unlike other books in the series.