The additions amount to "thousands" of additional seats across 22 routes flying from nine of the airline and operator's 14 UK bases.
Most of the extra flights are in April and October to meet early and late season demand, although there are a handful in May and July.
Destinations gaining extra flights include Majorca and Menorca in the Balearics, as well as several Greek islands and two Italian city favourites.
The additional seats are available from Birmingham, Bristol, East Midlands, Edinburgh, Glasgow, Leeds Bradford, Liverpool, Manchester and Stansted airports.
David Hills, Jet2's Chief Customer Officer, said: “We know how much our customers are looking forward to planning their summer holidays next year, and we are seeing continued demand for holidays earlier and later in the summer season as well as during the peak.
"In response, we have added thousands more seats and extended the season to a number of popular destinations for summer 2027, giving holidaymakers and independent travel agents even more opportunity to book early, plan with confidence, and choose the dates, flights and destinations that suit them best.”
Jet2 will offer the following extra services:
- Birmingham – season extensions to Crete (Heraklion) (from 7th - 28th April) and Kalamata (from 4th - 25th April)
- Bristol – season extension to Crete (Chania) (from 1st - 29th April)
- Edinburgh – season extensions to Reus (from 6th - 27th April) and Halkidiki (from 21st - 28th October)
- East Midlands – season extensions to Dubrovnik (from 4th to 25th April), Girona (from 5th to 26th April), Pula (from 2nd to 15th May) and Verona (from 13th to 27th October)
- Glasgow – season extensions to Dubrovnik (from 5th – 26th April) and additional flights from Reus (between 3rd - 24th April)
- Leeds Bradford – season extensions to Crete (Chania) (from 1st – 29th April), Crete (Heraklion) (from 7th – 28th April), Almeria (from 3rd – 24th April), Halkidiki (from 12th- 26th October) and Verona (from 13th – 27th October), plus additional flights to Palma (from 7th July – 24th September)
- Liverpool – season extension to Reus (from 4th – 27th April)
- Manchester – season extensions to Crete (Heraklion) (from 1st – 29th April), Menorca (from 6th – 27th April) and Naples (from 2nd – 23rd April)
- Stansted – season extension to Kefalonia (from 16th – 20th October)