Wawel Royal Castle and the Wieliczka Salt Mine are the two things almost every visitor to Kraków wants to see, and the good news is that you can do both comfortably in a single day. The trick is the order and the timing. Here is a plan that works.
Morning: Wawel
Start on the hill early. Book the first or second entry slot for the State Rooms, and add the Crown Treasury & Armoury for the coronation sword and the royal regalia. Two exhibitions, plus time to walk the Renaissance courtyard and the cathedral forecourt, comes to about two and a half hours. Aim to be finished by late morning.
Wawel sits a fifteen-minute walk south of the Main Square, so it is easy to reach on foot or by tram at the start of the day.
Midday: lunch and the train
Have an early lunch near the Old Town, then make your way to Kraków Główny, the main railway station. Trains run out to Wieliczka Rynek-Kopalnia in about 25 minutes, and the station is a short walk from the mine entrance. (Bus 304 from the centre is an alternative.)
Afternoon: Wieliczka
The Tourist Route underground takes around three hours from the top of the steps to the lift back up, so an early-afternoon tour leaves you plenty of daylight at the end. Book your tour language and your entry hour in advance — this is the part of the day most likely to sell out.
Remember it is around 17 °C down in the mine whatever the weather above, so carry a layer.
Booking order matters
Book Wieliczka first, because its guided tours in your language are the tighter constraint, then fit your Wawel slots to be comfortably finished beforehand. Give yourself a buffer between the two — the train and the walk at each end add up.
A gentler version
If a full day sounds like a lot, split it: Wawel one morning, Wieliczka the next. Both are more enjoyable unhurried, and neither is going anywhere.