check in at
phr. v..phr. v.. To register your arrival at a place like a hotel or an airport, so they know you are there.
phr. v.. To register one's presence upon arrival at a hotel, airport, or event, often as a required procedure.
We need to check in at the hotel now.
You should check in at the airport at least two hours before your flight departs.
After a long journey, the weary travelers were relieved to finally check in at the quaint seaside inn they had booked months in advance.
Commonly followed by 'at' for a location or 'for' for a service like a flight.
Contrast with its direct opposite, 'check out' (to leave a hotel), and the related phrasal verb 'check on' (to see if someone is okay).
I need to check in the airport.I need to check in at the airport.Use the preposition 'at' to specify the location where you are registering your arrival.