Local police said the group was met by police officers after the plane and its 170 passengers landed at Berlin Schönefeld airport.
Schönefeld before the Berlin wall came down was the major civil airport of East Germany (GDR), and the only airport serving East Berlin.
The men, from Southampton and aged between 25 and 28, were temporarily detained and charged under the Aviation Security Act.
which can carry fines of up to 25,000 euros (£19,700).
They could additionally face civil claims from the airline, and a possible worldwide air travel ban.
A Ryanair spokesperson : "This flight from London Luton to Bratislava (26 Feb) diverted to Berlin after a number of passengers became disruptive in-flight.
"We will not tolerate unruly or disruptive behaviour at any time and the safety and comfort of our customers, crew and aircraft is our number one priority.
"This is now a matter for local police."
This is the latest in a series of British stag party trips to get out of hand.
Another Ryanair flight was delayed in June after a member of a stag party ran on to the airport tarmac in Majorca as part of a dare.
and was promptly arrested by Spanish police.
Sources: BBC, Bild, Sky, AP,
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