Cromwell’s Castle — A Coastal Tower on Tresco

A Tower Built to Command the Seas

Perched on the shoreline of Tresco, Cromwell’s Castle stands guard over the narrow channel between the islands.
Built in the 1650s after the English Civil War, it replaced earlier fortifications and secured Cromwellian control of the Isles of Scilly.
Today, its round granite tower, ocean views, and windswept setting make it one of the most atmospheric coastal ruins in England.

It’s a place where history meets the open sea.

A Fortification from a Turbulent Era

The Isles of Scilly were the last Royalist stronghold to fall during the Civil War.
After capturing the islands, Cromwell’s forces built a heavy gun tower to control New Grimsby Sound and protect the anchorage.
However, when the monarchy returned, the tower remained in use and later gained an 18th-century gun platform.

Therefore, Cromwell’s Castle reflects centuries of shifting power and coastal defence strategy.

Exploring Cromwell’s Castle
1. The Round Gun Tower

The imposing granite tower rises two storeys above the shore.
Inside, a circular stair leads to the roof, where cannons once aimed at passing ships.
In addition, the thick walls and vaulted ceilings demonstrate the defensive engineering of the era.

2. The 18th-Century Gun Platform

Beside the tower sits a long, open platform added during the 1700s.
It held heavier guns designed to control the channel more effectively.
Moreover, its open sea views make it a stunning spot for coastal photography.

3. Coastal Paths and Island Scenery

The walk to the castle follows a beautiful seafront path from New Grimsby.
Waves, seabirds, and distant islands create a peaceful setting around the fortress.
Furthermore, the nearby ruins of King Charles’s Castle offer an excellent additional viewpoint.

Learn more at the English Heritage website

A Quiet Stronghold on a Beautiful Island

Although built for war, Cromwell’s Castle now sits in one of the most tranquil landscapes in the Isles of Scilly.
Its stark shape contrasts with turquoise water, wildflowers, and soft island light.
Additionally, its isolation gives visitors a strong sense of stepping back into the 17th century.

It’s not just a defensive tower — it’s a dramatic landmark shaped by sea, history, and solitude.

Visiting Cromwell’s Castle
How to Get There

Location: North end of Tresco, Isles of Scilly

Access: 15–20 minute walk from New Grimsby via coastal path

By Boat: Regular inter-island boats from St Mary’s

Opening Hours & Admission

Open daily

Free entry

Facilities

No facilities at the castle

Shops, cafés, and bike hire in New Grimsby

Uneven coastal paths

Nearby Attractions

King Charles’s Castle — Earlier Tudor fort high above the coast

Tresco Abbey Garden — Famous subtropical garden

Bryher — Peaceful island with beaches and viewpoints

St Mary’s Garrison — Extensive coastal defences

Together, these form the Scilly Islands Heritage Walk.

Why Visit Cromwell’s Castle?

The Cromwell’s Castle experience offers:

A unique 17th-century gun tower

Stunning coastal scenery

Free, open-air exploration

Easy access from village paths

Whether you love coastal walks, military history, or island landscapes, Cromwell’s Castle is a highlight of Tresco.
It’s not just a visit — it’s a step into history beside the sea.