The former swimming pool building had consent to be demolished as part of a 2017 planning application to provide a new £40 million complex, Splash, towards the east of the site.
As part of its plan to welcome back up to 4,500 guests this year, Butlin's has 'taken the opportunity to remove the pool' to create room for a new performance stage (BR/292/20/PL).
The holiday resort has also submitted plans for a new reception kiosk and changes to the car park layout (BR/307/20/PL).
Resort director Jeremy Pardey said: "As part of our strategy for 2021, we are considering social distancing, which will remain important for the foreseeable future.
"We want to get guests numbers up to 4,500, which is still 1,000 below what we operated at peak in 2019.
"We are having to create another theatre so we can double up on our shows, so everyone gets to see each pantomime and our star names.
"We've got a brand new pool which is much better."
According to planning documents, submitted by Walsingham Planning on behalf of Bourne Leisure, the new, temporary buildings would accommodate a performance stage and audience seating and would be in place for up to three years.
This will enable the resort capacity to be raised from the c.3,200 figure in the summer of 2020 to c.4,000 for 2021.
A spokesperson said: "Butlins need to make robust plans for 2021 and beyond so that the risk of having to limit operations and disappoint more guests next year and beyond can be minimised.
"The new temporary buildings must be in place in advance of the early May Bank Holiday. The erection of the buildings is scheduled to take three weeks but this assumes that the site is ready to accept it. This means that there will be site preparation works starting in March or as soon as demolition of the old pool allows."
Meanwhile, the objective of a new new kiosk is to enable cars to be 'processed faster and take them off the surrounding roads'.
The proposed kiosk is to be located in the existing car park on the north side of the Splash pool. It is hoped that this will 'improve current check-in and registration at the resort'.
The planning statement read: "It is also needed to ensure that the resort can follow best practice and help guests maintain social distancing.
"The proposal will not increase the capacity of the resort. It will simply allow it to operate more efficiently and provide a better and safer experience for guests."
The kiosk will have four service windows so that four cars can be processed at a time, 'with room for cars to manoeuvre', so that guests who have completed the process can move off and queuing guests can take their place.
"Some 53 cars can queue within the site and guests who have completed registration have a free route into all of the parking areas in this part of the resort," the planning statement read.
"There is a loss of 30 parking spaces as a result of locating the kiosk in an existing parking area together with the necessary manoeuvring areas, these are more than compensated for in the formalisation of the parking area at the rear of the Splash."
Mr Pardey said the resort's priority is to ensure that it remain safes and secure when it reopens.
He said the changes to the car park and registration process will also 'enable us to stop any traffic problems for the local community'.
He added: "The check-in sometimes causes issues with traffic for local residents. We are doubling the capacity so we can deal with more cars at a time.
"We are speeding up the roads for all those people. It makes it more efficient for our guests who don't have to queue. It's a win, win."
Comments about the applications can be made on Arun District Council's planning portal, using the reference numbers above.