No Priority to buy

Jet2 includes both an underseat bag and a full 56 × 45 × 25cm cabin bag on every fare. There is no Priority add-on, no boarding upgrade and nothing to remember at checkout.

For anyone used to Ryanair or Wizz Air, that is a real difference. The case you would need Priority to carry elsewhere travels free here.

The 10kg limit is the thing to watch

The cabin bag allowance is 10kg including wheels and handles. Because a hard-shell case at this size weighs around 2.8kg empty, you have roughly 7kg for contents.

That is enough for a week if you pack sensibly, but it is worth weighing before you leave. The size is generous; the weight is not.

The underseat bag takes a small case

At 40 × 30 × 20cm, the Jet2 underseat allowance is deep enough for a small wheeled hard-shell case — unlike British Airways, which allows only 15cm. If you want a wheeled underseat bag, Jet2 permits it.

Packing for both bags

With both allowances included, the sensible split is a cabin case in the locker for clothes and a small underseat bag for anything you want during the flight. Keep documents, medication and valuables in the underseat bag.