If you have 6 hours or half a day to spend in Isles of Scilly, here are some suggestions:
Explore the largest island of the Scilly archipelago. Walk around Hugh Town, visit the Garrison Walls and the Star Castle, and end the tour with a dip in one of the white sandy beaches. Time needed: approximately 3 hours.
Take a boat to Tresco Island and visit the world-renowned subtropical gardens at the Abbey. Wander through the palm trees, exotic plants, and tropical birds, then relax in one of the cafes. Time needed: approximately 2-3 hours, depending on how much you want to explore.
Hop on a boat for a tour around the smaller islands, such as Bryher or St. Martin's, and enjoy the secluded beaches, wildlife, and charming villages. Time needed: approximately 2-3 hours.
If you just want to relax, head to Porthcressa Beach, the closest beach to Hugh Town. Lounge on the sand or take a dip in the clear blue waters. Time needed: as long as you want!