HMS Perseus is a British submarine from World War II resting on the seabed off Kefalonia. This technical dive site sits at depths between 48 and 52 metres, requiring trimix certification and rigorous gas management. Access is by boat only, located 1600 metres from the shore. Visibility typically ranges from 10 to 30 metres, allowing for observation of the hull structure. While currents are generally mild, they can strengthen without warning. Due to the depth and potential for entanglement, this site is strictly for experienced divers with overhead environment training. Divers must coordinate with boat operators experienced in technical wreck diving to ensure safety.

Kato Lagadi is a small cove located on Kefalonia, Greece, featuring a diverse topography of reefs, caves, and drop-offs. Divers and snorkellers can explore several small caves and underwater arches. The site is accessed via a shore entry that requires a scramble down a steep rocky path. Depths range from 2 to 25 metres, with an average depth of 8 metres. Conditions are generally suitable for intermediate divers, with mild currents and visibility typically between 10 and 20 metres. Water temperatures fluctuate between 15C and 23C throughout the year. Hazards include the overhead environment within the caves and the presence of sea urchins.

Blue Caves in Zakynthos, Greece, features a series of natural arches and grottoes located 10 metres from the shore. This site is accessible by boat and offers depths ranging from 1 to 40 metres, with an average depth of 18 metres. Divers and snorkellers can explore the interior of the caves, where light reflections create distinct blue water conditions. Visibility typically ranges between 15 and 30 metres. Conditions include moderate currents and water temperatures between 15C and 21C, which may decrease near cave entrances. Due to boat traffic, this site is best suited for intermediate divers. Guided tours and air fills are available locally.

Agios Thomas in Kefalonia is a reef, cave, and cavern site accessible from the shore. Divers and snorkellers enter via a metal ladder located on a rocky slab, leading directly into a deep, rocky lagoon. The topography is defined by limestone formations, including underwater caves and natural jacuzzis carved into the rock. With depths ranging from 1 to 8 metres and an average of 5 metres, the site is suitable for beginners. Visibility typically spans 15 to 25 metres, and currents are generally mild. Facilities at the site include parking, showers, changing rooms, and a cafe. A typical dive lasts 60 minutes.

Pessada Beach in Kefalonia consists of two small coves divided by rocky outcrops. The second, more secluded cove features unique rock formations that create shallow, lagoon-like environments suitable for beginners. Snorkellers can observe a variety of marine life, including very common wrasses and rabbitfish. Other species frequently encountered include great barracuda, European parrotfish, Turkish wrasse, striped red mullet, and various bream. Less common sightings include the Mediterranean cardinalfish, painted comber, and the loggerhead sea turtle. Entry is from the shore, where water temperatures range from 16C to 27C. Be cautious of sea urchins when entering the water. Parking and a cafe are located nearby.

Koutsoupia Beach in Kefalonia, Greece, features a rocky seabed and deep green waters suitable for snorkelling. This reef site is best accessed by boat, as the alternative is a three-hour hike. The site is rated 4/5 for snorkelling and is suited for intermediate-level participants. Water temperatures fluctuate throughout the year, ranging from 16C in the winter months to 27C in August. While the site provides a quiet environment away from main tourist hubs, visitors can find a cafe nearby. The habitat supports a variety of Mediterranean reef fish and invertebrates typical of the region.

Amandakis Beach in Kefalonia is a reef site characterised by a large slanted rock formation that descends into deep water. The underwater topography features natural bridges, ravines, and deep pools. This site is suitable for intermediate divers and offers shore access. Conditions vary, with visibility typically reaching 20 metres or more. Divers should be aware of strong currents and surf, which are common hazards at this location. Facilities available at the site include parking and showers. The area is also highly rated for snorkelling.

Xigia Sulfur Beach is a distinctive site in Zakynthos defined by natural sulfur springs that flow directly into the sea, creating a milky-blue appearance. The underwater topography features karst caves and reef structures. Due to the influence of these springs and cliff shadows, water temperatures are generally cooler than at other local beaches, averaging 20°C in summer. Visibility may be slightly reduced by the sulfur content. The site is accessible from the shore and is suitable for beginners, although the water can be deep. Facilities at the location include parking, a cafe, and showers.