Chessington World of Adventures and Thorpe Park will be closed during a number of off-peak weekdays in 2016.
The move is a diversion from the parks’ traditional strategy of opening every day from when their seasons begin in March each year.
Chessington will host a preview weekend for annual pass holders on 12/13 March, while its main season will commence on 18 March.
It will then open every day until 31 October, with the exception of 19-20 and 26-27 April, 10-11 and 17-18 May, 13-14, 20-21 and 27-28 September and 4-5 and 11-12 October.
Thorpe Park will open on the weekend of 12/13 March, but this is also expected to be announced as an annual pass preview weekend.
Its main season begins on 17 March and will open every day until 2 November, excluding 13-14, 20-22 and 27-29 September and 4-6, 11-13 and 18-19 October.
Cost base
Park operators Merlin Entertainments have suffered considerable losses in revenue at its theme parks since the Smiler rollercoaster crash at Alton Towers in June this year.
The company said in trading statements earlier this year that it expected the effects of the accident to continue into 2016, but that it would be able to “reset” its cost base before the season commences.
Merlin’s other UK theme parks, Legoland Windsor and Alton Towers, which will open on 19 and 12 March respectively, have not yet announced any midweek closures during their 2016 seasons.