Chesil Cove & Portland Shore Dive

Image credit: Wikimedia Commons

Overview

Chesil Cove is situated at the extreme southern end of Chesil Beach, a massive 18-mile-long shingle barrier that connects the Isle of Portland to the mainland of Dorset on England’s south coast. Because the high cliffs of Portland shelter the cove from the prevailing easterly and northerly winds, this site frequently offers calm, accessible diving when other locations along the coast are blown out.

The topography of the dive site consists of the underwater continuation of the pebble beach, which slopes down rapidly before transitioning into a flat sandy and silty seabed interspersed with patches of eelgrass and low-lying rocky reefs. The maximum depth generally does not exceed 14 meters (45 feet), making it an ideal location for novice divers. It is frequently utilized by local dive clubs as a reliable spot for the sheltered water components of the open water course. For divers living in the UK looking for the best places to learn fundamental cold-water skills without the need for a charter boat, Chesil Cove is highly recommended.

The Dive Experience

Access to Chesil Cove is entirely from the shore. Divers typically park along the sea wall in the village of Chiswell, gear up, and walk down the steep pebble bank. Entering and exiting the water requires caution; the pebbles shift easily underfoot, and divers must be extremely careful if there is a south-westerly swell, which can create a powerful shore dump (breaking waves on the steep beach).

Because it is a UK coastal site, appropriate thermal protection is required year-round. As outlined in standard travel and packing resources for temperate waters, a drysuit is heavily recommended, though a thick 7mm semi-dry suit may suffice during the peak summer months when the water temperature reaches 16°C or 17°C (61°F to 63°F).

What You’ll See

Chesil Cove is famous within the UK diving community for its macro marine life and seasonal events. The most notable of these is the annual cuttlefish migration. Every year, typically between May and June, hundreds of common cuttlefish (Sepia officinalis) arrive in the shallow waters of the cove to breed and lay their black, grape-like egg clusters among the seaweed and submerged debris. During this period, divers can observe the complex mating behaviors and rapidly shifting color displays of these highly intelligent cephalopods.

The site is also widely recognized as one of the best locations for night diving on the south coast. After dusk, the sandy bottom comes alive. Divers frequently encounter bobtail squid, various species of pipefish, and hunting octopuses. It is also common to spot John Dory—a highly distinctive, laterally compressed fish—slowly stalking prey over the sand.

Additionally, due to centuries of intense maritime activity and countless shipwrecks along Chesil Beach, the seabed in the cove is littered with historical debris. Divers frequently stumble across heavily encrusted fragments of old wooden sailing vessels, massive iron anchors, and scattered antique bottles.

Planning Your Dive

Chesil Cove is subject to local tides, though the currents within the extreme southern corner of the bay are generally mild compared to the ferocious tidal races further offshore around Portland Bill. Divers must always check local weather forecasts and tide tables before entering the water. The site is a public beach, so divers share the area with fishermen; it is highly recommended to carry a cutting tool to deal with discarded fishing line and to tow a surface marker buoy (SMB) to alert boat traffic to your presence.