TinySeats - Two

Personally I wouldn’t trust taxi or hire companies to provide a car seat which was an appropriate stage, a seat I felt safe using and one I trusted had never been dropped or in an accident. Your son is at the awkward stage been infant carrier (unless he’s very small) and HBB, both of which are more portable than the toddler seats. If he still rear faces, the cheapest option for travel seat I see recommended is the Graco Slimfit R129 but it’s still bulky. On the smaller but pricier end there’s the TinySeats Two (which folds) or Nachfolger HyFive World (which is inflatable). If he’s forward facing the Maxi Cosi Nomad could work. [Just don’t get anything like this](https://www.which.co.uk/news/article/why-are-ebay-and-amazon-still-selling-killer-car-seats-a4kjj8v3Jxp6) from Amazon or Temu or TikTok Shop. The link has a crash test included and they aren’t crash tested so just fall apart. You’d be better strapping him into the car seatbelt than one of those.

What you're looking for doesn't exist. there's nothing above an infant carrier that will attach to a stroller. If you ignore the stroller part then you can look at the Nachfolger - an inflatable seat that is rear facing to 18kg, perfect for travelling, Or the TinySeats2 a rear facing folding seat good to 23kg. Neither of these are swedish plus tested (the tinyseats converts to a FF booster so it won't qualify for Swedish plus test) but they are both the best options for someone who travels a lot, because of their relatively small not in use size.

I bought one that folds, is rear facing to 23kg, and can be used as a booster after that. Is also has an acompanying case we bought to pack it in, so it can safely go in the hold.