St Michael's Mount will be free to visit for residents who live locally - but tourists will have to pay a charge.
The island's harbour and village will be made free 12 months of the year but only for residents in Marazion.
For everyone else, access will only be free outside the main tourist season.
The changes follow a backlash from locals, who objected to a controversial £14 entry fee which was introduced during the pandemic.
Although the fees were initially brought in to reduce crowds during the pandemic, staff at the mount say there was a notable difference in the general manageability of the island.
In an update on their website, owners St Aubyn Estates said: "What we found was that timed entry significantly relieved pressures on the island’s staff and infrastructure, its boating services, catering facilities, toilets, paths and lawns as well as reducing the pressures on Marazion and its community from the ever increasing number of people wanting to visit the Mount.
"The National Trust and the Estate are aware that those changes impacted the community around the Mount, and these new access initiatives for local communities are specifically designed to address that."
As well as providing free access to the grounds for Marazion residents, up to 1,000 single-use passes will be made available to people who live in West Cornwall.
The 'Mount Memories Pass' will given groups of up to four people free access to the castle and gardens who wish to celebrate a special occasion, or have a link to the island.
'Balancing the needs of residents and visitors'
CEO Harvey Thomas said: “As the country opened up and visitors chose to come to Cornwall, it was crucial to ensure a safe level of people on the island at any one time, and a timed ticketing system was introduced, which has worked very well.
“We still face a complex situation. We know that the number of people wanting to visit west Cornwall and St Michael’s Mount has risen and will continue to rise, especially with uncertainty around overseas travel.
"That increases pressure on facilities on the Mount, the town and our wider local community. Continuing to manage numbers and control access to the Mount is key to balancing the needs of local residents and visitors.
“At the same time, these new arrangements reflect how important our local community is to us and that we appreciate how special the Mount is to so many people in Cornwall.
“We also hope that the introduction of the Mount Memories Pass will create amazing new memories as well as reviving happy old ones.”