Meet the site
Grindal Island is an 81-hectare, 26 m-high island in Lincoln National Park, among the scatter of islands in Thorny Passage south of Port Lincoln. The Marine Life Society describes a jetty on the sheltered west side and deeper reefs on the south side, reaching about 20 m, with large boulders, bommies and swim-throughs on a rocky bottom covered in seagrass and kelp. The island is best known to visitors as an alternative venue for Port Lincoln's sea lion swims: Calypso Star Charters takes guests to Hopkins, Grindal or Blyth Island depending on which offers shelter on the day. Australian sea lions haul out on the island and enter the water to investigate swimmers, behaving much as they do at Hopkins. For scuba divers, the south-side reefs offer a varied temperate dive. Schools of sweep and silver drummer move over the boulders, large western blue groper cruise the reef, and the bommies and swim-throughs are coated in sponges and algae. The Society warns that visibility is sometimes poor, as tidal streams through Thorny Passage can carry sediment. Grindal suits snorkellers on tour and Open Water divers with a boat. It combines well with nearby Memory Cove, Taylors Island or Lewis Island for a day of island diving in Lincoln National Park. The sheltered jetty side is handy for a surface interval, and the island's position means it often offers a lee when south-westerly swell is running through the outer passages. As with all sea lion encounters, keep movements slow, let the animals initiate contact and give any large bull a wide berth. Tidal streams can run strongly around the island's points, so plan deeper dives for slack water and carry an SMB. The combination of an easy sea lion swim and a proper boulder dive makes Grindal a good all-round island for mixed groups of snorkellers and divers.
Research this site before booking Stored site notes may be historical. These questions highlight gaps without turning old instructions into a current dive plan.
Grindal Island – Sea Lions is recorded as Island in Eyre Peninsula. The listed access is boat (day trip). Confirm the actual meeting point, route and permission to visit; a map pin does not establish any of these.
Topics flagged by the stored research
These are questions prompted by the existing notes, not a verified or complete hazard assessment.
- Current and timing
- Ask how the operator assesses the current window for the actual route. Historical tide notes are not a departure instruction.
Historical access notes exist for this record, but have not been independently verified for current use. Request current directions from the operator or site manager rather than following an old entry description.
Questions, answered
Is Grindal Island – Sea Lions suitable for my certification?
The record lists Advanced Open Water. That does not establish suitability for every route or day. Share your training, recent experience and equipment needs with the operator and ask about the specific proposed dive.
Can I book Grindal Island – Sea Lions through YouDive?
YouDive is an independent research directory. Contact an operator directly to confirm whether it currently runs the trip, the inclusions and the booking terms.
What you might see
Australian sea lions, sweep, silver drummer, western blue groper, magpie perch, wrasse, sponges, kelp, seagrass
Location
81-hectare island (26 m high) in Lincoln National Park south of Port Lincoln, with a jetty on its sheltered west side, sea lion interactions and deeper reefs on the south side to 20 m.
Facilities nearby
Lincoln Cove Marina and ramps in Port Lincoln.
Before you make plans
Conditions, access and operator schedules can change. This is a location guide, not a dive plan. Ask a local operator about current conditions and suitability for your training and experience.
Sources & further reading
marinelife.org.ausouthaustralia.comRecord updated 27 Sept 2026. Source claims are being reviewed.