Ryanair is trying to reduce its airport service costs.
Ryanair is to increase its check-in charges by £1 to £4 per passenger and by £2 to £8 per bag from Tuesday to try and reduce its airport costs.
The Irish no frills airline is encouraging travellers to check-in online and take only hand luggage.
Rising oil prices and an economic slowdown have raised concerns about the profitability of airlines.
Ryanair says 40% of its passengers already check-in online so do not pay these additional charges.
It is the second time this year that the airline has raised its passenger charges and may not be the last.
Flight London to Dublin: £14.99
Tax and fees: £19.75
Aviation insurance & wheelchair levy: £4.37
Airport check-in: £4.00
Hold luggage: £8 per bag
Credit card charge: £3
Source: Ryanair website
"We will continue to increase baggage fees until half of our passengers check-in online," said Ryanair spokesperson Peter Sherrard.
"[It] will allow us to reduce check-in and handling costs and pass on these savings to our passengers in the form of Europe's guaranteed lowest fares," he said.
Many Ryanair passengers will find that they pay more in taxes, fees and charges than for the flight itself.
To take one example, an early one-way flight from London Stansted to Dublin on Saturday 10 May is currently advertised at £14.99.
On top of that, passengers will pay £19.75 in taxes and fees.
In addition, there's £4.37 for aviation insurance and the "wheelchair levy".
If you want to check-in in person at the airport, that will cost you an extra £4 from Tuesday.
And for every piece of luggage you want to check-in, add £8.
Plus, at the end of the transaction, you will be charged £3 if you pay by credit card or £1 by debit card.
So, if you travelled to Dublin on Saturday with two pieces of luggage, you could end up paying an additional £47.12 on top of your £14.99 flight.
No-frills rival Easyjet charges passengers £5 for every piece of luggage they check in online, rising to £10 if it is not paid for until the airport.
Separately, Ryanair was deemed the worst for passenger amenities in a survey of users done by the Tripadvisor website.
Amongst British travellers responding to the survey, Ryanair was seen to have the worst food.
The 1,600 voters from around the world rated Virgin Atlantic's amenities the best.