Horseshoe Bay, the long north-facing beach at the end of Magnetic Island's main road, hides two modern wrecks listed in the North Queensland Underwater Explorers Club's local wreck index. The Argonaut II was a double-masted auxiliary ketch of about 200 tonnes and 40 m length that operated as a licensed floating restaurant before catching fire and sinking in 1978; she lies in about 6 m, roughly 300 m west of the eastern inlet. The Balmunda, a commercial prawn trawler, caught fire and sank at her mooring in 1981 and lies about 500 m offshore in 3–6 m.

Neither wreck is well documented as a dive. Both burned before sinking, and more than four decades in a shallow, silty bay have reduced them to hull remains and machinery colonised by algae, sponges, soft corals and small fish. They are best treated as a pair of shallow curiosities for divers staying at Horseshoe Bay with access to a small boat, rather than as destinations.

The bay also contains the Morning Light, a schooner later used as a lighter, lying in 0–2 m about 40 m from the creek mouth, and because it faces north, the bay is calm in a south-east trade wind when the island's eastern bays are rough. Visibility, however, is usually poor – 2–6 m – because of the sandy, silty bottom and boat traffic. Horseshoe Bay has a stinger net in season, a ramp, cafes and a pub, making it an easy base.

The sites are in a busy boating area with jet-ski and water-sport hire, so a dive flag and a boat tender are essential. Data confidence is low: positions come from the club index, and current condition is not recorded.

Magnetic Island is reached by SeaLink passenger ferry from the Breakwater terminal in Townsville to Nelly Bay (about 20 minutes, frequent daily services) or by the vehicle ferry from Ross Street, South Townsville (about 40 minutes). Buses, hire cars and 'topless' mokes run from the Nelly Bay terminal to Arcadia, Horseshoe Bay and Picnic Bay. Horseshoe Bay is at the end of the main road on the north coast (about 20 minutes by bus from Nelly Bay).

There is a boat ramp and a large sandy beach. The wrecks lie offshore in the bay: Argonaut II about 300 m west of the eastern inlet and the Balmunda about 500 m offshore. A small boat launched from the ramp is the practical approach, with GPS marks obtained locally; a long surface swim from the beach is possible but crosses a busy boating and jet-ski area.

Magnetic Island's bays are sheltered from different winds depending on which side they face. The dominant south-east trade winds (15–25 knots, April–September) chop up exposed eastern and southern bays and stir up silt, so the island's best diving comes in the calmer months of August–December and on mornings before the sea breeze. Visibility is usually 3–8 m and occasionally 10–15 m; it drops sharply after strong winds, big spring tides and wet-season rain (January–April) when Ross River and Burdekin run-off discolour the water.

Dive at slack water, ideally high tide. Sargassum seaweed blooms in the hotter months can smother shallow reef flats. Marine stinger season (box jellyfish and Irukandji) runs roughly November to May – wear a full-length stinger suit or wetsuit with hood and gloves, carry vinegar.

Stinger nets are installed at Alma Bay, Picnic Bay and Horseshoe Bay in season. Horseshoe Bay faces north, so it is sheltered in the south-east trades but exposed to northerly winds and swell in the build-up and wet season.

Drop a shot on sand beside each wreck in turn and circle the remains at 3–6 m; both are small, so combine them in one dive by boat or do two short dives.

No regular operator; NQUEC club and private boats. Nearest dive centres for gear hire, fills and local advice: Pleasure Divers Magnetic Island, Adrenalin Snorkel & Dive.