Key Facts

Key facts at a glance

• 📍 Location: West Sussex

• 🥾 Distance: 13 km (circular)

• ⛰️ Height gain: 54 m

• 🗺️ Map: OS Explorer OL8 – buy here

• 🚗 Start point: Thorney Road/Thornham Lane junction (Grid ref. SU 766 051)

• 🌊 Terrain: Easy coastal path, muddy in places, tidal sections

• 🔑 Access: Footbridge, via MoD security gates

Affiliate Disclosure: This post contains affiliate links. If you book through them, we may earn a small commission at no extra cost to you. Thank you for supporting Islandeering!

Why Walk Thorney Island?

Thorney Island sits on the southern coast of England, tucked into the beautiful Chichester Harbour Area of Outstanding Natural Beauty (AONB). This 13 km circular route is one of West Sussex’s most fascinating walks — blending sweeping harbour views, wildlife-rich mudflats, and poignant reminders of the island’s RAF and military heritage.

Expect a mix of wide-open skies, tidal creeks alive with oystercatchers, curlews, and Brent geese, and curious encounters with MoD security gates that stand in stark contrast to the peaceful coastal scenery beyond.

This walk is perfect for:

• 🐦 Birdwatchers – rare waders and waterfowl thrive here.

• 🌿 Nature lovers – mudflats, saltmarsh, and Pilsey Sands are internationally protected habitats.

• ⚓ History buffs – from RAF control towers to SAS memorial benches.

• 🚶 Casual walkers – easy terrain, but muddy in places after rain.

Route Description: Step-by-Step

1. Emsworth to Thornham Marina

Begin at The Deck Café, Emsworth Yacht Club (a great place to fuel up before or after). From here, follow signs for the Sussex Border Path, cross the stile, and head south past the Sea Scouts hut onto the dyke path. Soon you’ll reach Thornham Marina and Pains Boatyard, with boats lining the water.

2. Crossing the Great Deep

Continue across the lifting bridge and follow signs to the MoD Eastern Security Gate. You’ll need to buzz the intercom for access — CCTV cameras and barbed wire create a surreal moment. Once inside, the views transform: reclaimed mudflats alive with wildlife, the salty tang of the harbour, and open skies.

3. St Nicholas Church & RAF History

Near St Nicholas Church, at low tide you can continue along the foreshore; otherwise, take the inland route behind the sailing club. Soon you’ll see the island’s disused RAF runway, control towers, and old masts, reminders of Thorney’s 20th-century military past.

4. Pilsey Island & Bird Hide (Halfway Point)

South of Thorney, at Longmere Point, a bird hide marks the halfway stage. Pilsey Island itself is an important nature reserve — public access is restricted, but you can skirt the sands at low tide for superb harbour views.

👉 Download the OS Maps app or carry the OS Explorer OL8 Chichester for safe navigation. Find maps here.

5. West Coast & Return to Emsworth

Turn north along the west coast path, passing the moving SAS memorial benches, before crossing back over the Great Deep via the West Gate. The final stretch hugs the shoreline, leading back through Emsworth Yacht Club and The Deck Café.

Facilities on the Walk

• On the island: None (bring water and snacks).

• Nearby:

  • The Deck Café, Emsworth Yacht Club – full menu & harbourside views.

  • Scout Hut, Prinstead – teas (weekends, Apr–Oct).

  • Thornham Marina – light snacks.

  • Emsworth village – pubs, cafés, supermarkets. Try The Coal Exchange for rotating ales, hearty food, and a roaring fire.

👉 Top tip: A stainless steel insulated flask is perfect for keeping drinks cold on this walk. Check recommended hiking flasks.

Planning Your Thorney Island Walk

• 🅿️ Parking: Junction of Thorney Road/Thornham Lane (SU 766 051).

• 🚍 Public transport: Emsworth train station, then short walk to start.

• ⏱️ Time: 3.5–4.5 hours depending on pace and tides.

• ⚠️ Notes: Path can be muddy; check tide times before setting out.

Final Thoughts

The Thorney Island Walk is a rare blend of wildlife, history, and coastal scenery. Where else can you buzz through MoD gates, stroll beside RAF runways, and watch flocks of curlews rise above golden mudflats — all in a half-day’s walk?

Whether you’re a seasoned hiker, a weekend wanderer, or a birdwatching enthusiast, this walk offers something unforgettable. Pack your waterproofs, grab your OS map, and let Thorney’s windswept shores work their magic.

👉 Ready to explore? Download the GPX route or grab a copy of Islandeering for more hidden island walks across Britain.

Please enable JavaScript in your browser to complete this form.

Email *

Download Thorney Island route gpx