English Heritage is to submit plans to build a new visitor admissions building at Dover Castle.
The building will stand almost twice the size of the existing block if the council approves the application.
Tracy Wahdan, English Heritage visitor operations for the South East said: 'The current building is no longer adequate for the numbers of people visiting the castle.
'With more than 300,000 visitors a year to the castle, we need a larger admissions building so that we can provide visitors with quality facilities.'
English Heritage is hoping for a decision from Dover District Council before the end of November ready for the summer season.