The Dublin-based carrier said it made the decision as flights are being stalled due to a lack of space in overhead lockers.
From November 1 those travelling on the low-budget airline will only be able to carry a bag no larger than 35cm x 20cm x 20cm on board, with larger wheelie bags being placed in the hold free of charge.
The luggage drop-off will take place at the boarding gate instead of at check-in.
Urgh so women with handbags will be charged for the carry on luggage. But men won't as they don't tend to use handbags. There'll be war.
— Dr Jennifer Kavanagh (@quiatimet) September 6, 2017
Only priority customers, who pay £5 to £6 extra, will continue to be able to keep two bags with them on the aircraft.
Chief marketing officer for Ryanair Kenny Jacobs said he hopes the changes will ‘eliminate flight delays’ caused by not having sufficient overhead cabin space on busy flights, as ‘too many customers are availing of the improved two free carry-on bags service’.
The company claims 97% of flights in August had high hand luggage loads, leading to lags in boarding.
Mr Jacobs added: “These bag policy changes will cost Ryanair over 50million (£46million) per annum in reduced checked bag fees.
“However, we believe offering bigger bags at reduced fees will encourage more customers to consider checking in a bag, which will reduce the high volume of customers we have with two carry-on bags at the boarding gates, which is causing flight delays due to large numbers of gate bag and cabin bag offloads.”
The changes will apply to all existing and future bookings from November 1.
Meanwhile, customers reacting online have been left less than impressed by the changes.
Some have labelled the move as sexist, as women won’t be able to board with a handbag and their small luggage bag.
Other frequent flyers have complained that they now have to wait for the luggage at reclaim, which will delay their future journeys.