EasyJet will start charging customers a premium for the use of overhead lockers on flights.
The airline says it is tightening its hand luggage rules to "improve boarding and punctuality".
Passengers travelling on its standard fares will only be entitled to bring a bag on board if it can fit under the seat in front from February 10th.
Currently, all customers are allowed to fly with a cabin bag measuring up to 56cm by 45cm by 25cm, enabling them to put small wheelie suitcases into overhead lockers.
Under the new rules, passengers who want to travel with an additional bag of this size as hand luggage must pay an extra fee. The charge will also entitle them to select a seat at the front of the aircraft or one with extra leg room.
Those who buy a more expensive Flexi fare or are members of the carrier’s frequent flyer scheme will also continue to be allowed to take one small and one large item of hand luggage with them, subject to space on board.
EasyJet does not apply a weight limit to cabin bags. It described its size restrictions as “among the most generous for air travel”.
Customers with an existing booking for travel from February 10th who do not want to buy one of the optional extras will be able to check in a larger cabin bag in the aircraft hold free of charge.