The earliest time you can check-in at a desk is 24 hours before scheduled departure of your flight. 

Access to the departure area is possible a maximum of six hours before departure, provided it is open for other departures.

Self service check-in machines can be used in most cases, when going on a scheduled flight.

Domestic flights
If you have a ticket, seat reservation and hand luggage only, you have to be at the gate at least 10 minutes before scheduled departure. If you travel with luggage, this must be checked-in at least 20 minutes before scheduled departure time. If you are going on a transit flight via Copenhagen, check-in must be completed at least 30 minutes before scheduled departure.

International flights
Check-in must be completed at least 30 minutes - are you travelling with Air Baltic or Ryanair 40 minutes - before scheduled departure.

If you are going on a longer journey and carry more pieces of luggage to be checked through to your final destination, you have to check-in in good time, so that the check-in can be completed at least 30 minutes (Air Baltic and Ryanair 40 minutes) before scheduled departure time.

Check-in to a KLM flight
With baggage: KLM recommends passengers to check-in to its flights at least 60 minutes before the scheduled departure time.
Without baggage: KLM recommends passengers to check-in to its flights at least 45 minutes before the scheduled departure time.
The check-in must in both cases be completed at least 30 minutes before scheduled departure time.

Charter flights
Look at your travel paper issued by the travel agency.

Remark:
If you are travelling with many pieces or bigs sized luggage, are travelling with a live animal or having special luggage, it is always a good idea to check-in in good time - not more than 24 hours in advance though,