As reported by @OrangeDog on Gitter, there's an unfortunate mismatch between Servlet's default cookie name (JSESSIONID) and Spring Session's default cookie name (SESSION). This mismatch means that the server.servlet.session.cookie.same-site property has no effect when using Spring Session. I think that setting server.servlet.session.cookie.name=SESSION will gets things working. We should confirm that this is the case and also see if there's something that we can do so that this works out of the box.