Meet the site
The Sir Joseph Banks Group is a scatter of 17 islands at the southern end of Spencer Gulf, about 25 km off Tumby Bay, named by Matthew Flinders in 1802. The Marine Life Society describes clear water with good fish life in 10-20 m, and notes that larger charter vessels from Tumby Bay serve the group. Spilsby Island, at 468 hectares, is the largest, with a jetty on its sheltered west side, a 1 km beach and rocky dive sites on the south-east side. The Society describes it as a major charter centre with diver accommodation. Fish life on the reefs is rich: the Society lists silver drummer, trevally, yellowtail, bullseyes, cowfish, blue groper, leatherjackets, wrasse, boarfish, zebrafish, sweep and morwong. The boulders and ledges carry sponges and algae, and the clear water of the outer gulf makes for good visibility. Nearby Duffield Island (7.9 ha, 750 m from Spilsby) offers a 10 m dive with plenty of fish including large blue groper. The islands are part of the Sir Joseph Banks Group Conservation Park and marine park, and several host seabird and sea lion colonies – Langton Island's sea lions are one of the group's highlights. Spilsby suits divers with a capable boat or a charter who want to explore a little-dived island group. It is a good base for a few days of island diving in calm summer weather. Carry a VHF radio or satellite beacon, full oxygen and first-aid kits, and enough fuel for a detour, as the group is a long way from help and weather in lower Spencer Gulf can change quickly. Check the marine park zoning map before fishing or collecting, and respect landing restrictions on the smaller islands, which protect seabird and sea lion breeding sites.
Research this site before booking Stored site notes may be historical. These questions highlight gaps without turning old instructions into a current dive plan.
Spilsby Island 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 Spilsby Island 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 Spilsby Island 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
Silver drummer, trevally, yellowtail scad, bullseyes, cowfish, western blue groper, leatherjackets, wrasse, boarfish, zebrafish, sweep, morwong, sponges, kelp
Location
Largest island (468 ha) of the 17-island Sir Joseph Banks Group, about 25 km off Tumby Bay, with a jetty on its sheltered west side, a 1 km beach and rocky dive sites on the south-east side in 10-20 m.
Facilities nearby
Island jetty; Tumby Bay ramp and services.
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.auRecord updated 27 Sept 2026. Source claims are being reviewed.