The airline and operator will serve Copenhagen from Birmingham next winter, while Bristol will gain a Cologne route.
Elsewhere, Jet2 will begin flying to Gdansk from East Midlands airport and to Tallinn from Leeds Bradford airport.
Manchester airport, meanwhile, will gain extra Thursday and Sunday services to Berlin, upping frequency on that route to four-times-weekly.
The biggest expansion is at Stansted where Jet2 is adding extra Monday and Friday services to Krakow, extra Thursday and Sunday services to Prague and extra Thursday and Sunday services to Vienna.
All three routes will go up to four-times-weekly as a result next winter.
In total, Jet2.com and Jet2CityBreaks will operate 60 routes to nine Christmas market destinations from 12 of its UK bases next winter.
The new routes and additions to existing routes constitute more than 30,000 additional seats.
City breaks are available on a £60pp deposit and include 22kg hold luggage, 10kg hand baggage and a choice of two- to five-star accommodation.
Steve Heapy, Jet2.com and Jet2holidays chief executive, said: “This announcement represents a significant expansion to our winter 2026/27 Christmas markets programme, giving customers and independent travel agents even more choice.
"We are delighted to be putting four brand-new new routes on sale from four of our UK airport bases and adding additional capacity from others too. The expansion comes in direct response to the continued demand we are seeing from customers and independent travel agents."
