This private island is situated just off the north coast of Brittany, 3 km (2 miles) from the village of Roscoff, from which ferry connections to the UK can be made.

The island is connected by a sandy beach at low tide to the Perharidy peninsula. The owner of the island enjoys right of way access through the private grounds of the peninsula, ensuring that the island's privacy is maintained even at low tide.

The principal feature of Ile Jacobin is its castle, which has been well maintained and is in good condition. The castle has a large entry hall, 6 main rooms, kitchen, cellar and a 1800 sq. foot (600 sq. metre) terrrace on the second floor, offering panoramic views of the sea and the Brittany coast.

The island's climate is mild, moderated by the Gulf Stream. Palms, eucalyptus and other sub-tropical vegetation is present on the island, giving it a park-like atmosphere. Also present is a small tower on the island's southern end. Phone, water and electricity lines connect the island with the mainland.