Diving and snorkeling in Port Arthur
Today, Thursday, October 29, 2026 · local time (GMT+11) · Tasmania, Australia Today, Thu, Oct 29 · GMT+11- Slack water
- 11:40 pm–1:00 am, 3:20–5:00 am, 10:20–11:00 am and 6:10–6:50 pm
- Swell
- 13 ft, 10 s
- Water and suit
- 56.7 °F · 7 mm semi-dry suit
- Likely visibility
- Poor
- Water (satellite)
- Murky
Today, Thursday, October 29, the best time to dive in Port Arthur is 5:30 am to 8:30 am. It's a poor day (0/10). Visibility is likely poor. Water at 56.7 °F: a 7 mm semi-dry suit, with hood, gloves and booties. The best day this week is Wednesday, November 4, at 6/10.
Not a day for shore diving: swell, wind, current or storms during the best window. If you go, go with a dive shop and only if they give the OK.
Your diving day in Port Arthur at a glance
The strip runs from midnight to midnight, local time. Daylight on top; then the tide with its slack water (purple bands), the conditions hour by hour and the best times.
Today in detail
Likely visibility: poor- Slack water today: high tide 12:12 am (11:40 pm–1:00 am), low tide 4:14 am (3:20–5:00 am), high tide 10:42 am (10:20–11:00 am) and low tide 6:27 pm (6:10–6:50 pm)
- Likely visibility: poor. Swell (up to 13 ft at 10 s) and wind over the last few days have stirred up the water. Based on the last 24 hours of data.
- Water at 56.7 °F: a 7 mm semi-dry suit, with hood, gloves and booties.
- Snorkeling: better not, with these waves, wind or current.
- Night dive: dark from 8:20 pm. Waning gibbous (89%): a bright night.
Slack water comes from the tide: in inlets, channels and between islands the water can keep running for an hour or two after. Ask the local dive shop.
Never dive alone and check with the local dive shop: this rating is a guide, not a substitute for a professional.
The water, as seen by satellite
The satellite saw murky water in the sea off Port Arthur, within 3.1 mi (4 pixels of 2.5 mi; Kd490 = 0.30 m⁻¹). Kd490 measures how fast blue light fades with depth: the higher it is, the murkier the water, from plankton, suspended sand or rivers.
Very clear: under 0.06 m⁻¹ (open tropical sea: Red Sea, Caribbean). Clear: up to 0.12. Slightly murky: up to 0.25. Murky: above that (coasts with rivers, estuaries).
It's what the satellite saw that day, the last one without clouds: since then, swell, wind or rain may have changed it. The likely visibility above is today's.
Satellite: NOAA CoastWatch, Kd490 from the S-NPP VIIRS (experimental product), 2.5 mi pixels. It only shows where the seabed drops below 20 m close to shore: in shallower water the satellite sees the bottom and makes the water look murkier than it is. Sources and licenses
Diving forecast for the next 7 days
| Day | Rating | Best times | Swell | Visibility | Water |
|---|---|---|---|---|---|
| Today | 0 poor day | 5:30–8:30 am | 13 ft · 10 s | Poor | 56.7 °F · 7 mm semi-dry suit |
| Fri 30 | 3 fair day | 6:40–7:30 pm11:00 am–12:20 pm | 7.0 ft · 9 s | Poor | 56.7 °F · 7 mm semi-dry suit |
| Sat 31 | 2 poor day | 5:50–7:30 am12:30–1:20 pm | 5.7 ft · 9 s | Poor | 57.0 °F · 7 mm semi-dry suit |
| Sun 1 | 3 fair day | 5:50–7:30 am1:10–2:10 pm | 4.7 ft · 8 s | Poor | 56.7 °F · 7 mm semi-dry suit |
| Mon 2 | 2 poor day | 5:50–6:30 am2:10–3:20 pm | 6.8 ft · 10 s | Poor | 56.7 °F · 7 mm semi-dry suit |
| Tue 3 | 5 average day | 2:40–4:30 pm9:10–11:00 am | 4.1 ft · 10 s | Poor | 57.0 °F · 7 mm semi-dry suit |
| Wed 4 | 6 average day | 5:50–6:30 am9:50–11:50 am | 3.3 ft · 9 s | Poor | 56.8 °F · 7 mm semi-dry suit |
Each day's rating comes from the swell, waves, wind, current, slack water, daylight and likely visibility. The forecast reaches about 7 days.
Dive sites, wrecks and dive shops nearby
Map: OpenFreeMap · © OpenMapTiles · © OpenStreetMap contributors
- Port Arthur Jetty Fish seen: Trachinops caudimaculatus, Ground Mullet, Blue-throated wrasse, Variable Triplefin 0.4 mi
- Saftety cove nth Fish seen: Acanthaluteres vittiger, Meuschenia australis, New Zealand banded wrasse, Long-finned pike 1.0 mi
- Isle of the Dead Fish seen: Blue-throated wrasse, New Zealand banded wrasse, Trachinops caudimaculatus, Ground Mullet 1.4 mi
- Port Arthur/Stewarts Bay Fish seen: Blue-throated wrasse, Trachinops caudimaculatus, New Zealand banded wrasse, Senatorwrasse 1.4 mi
- Point Puer Fish seen: Trachinops caudimaculatus, Blue-throated wrasse, New Zealand banded wrasse, Senatorwrasse 1.7 mi
- Stinking Bay Fish seen: Trachinops caudimaculatus, Long-finned pike, Blue-throated wrasse, Senatorwrasse 2.1 mi
- Safety Cove Fish seen: Trachinops caudimaculatus, Blue-throated wrasse, New Zealand banded wrasse, Pseudolabrus rubicundus 2.5 mi
- Surveyors Cove Fish seen: Blue-throated wrasse, New Zealand banded wrasse, Acanthaluteres vittiger, Senatorwrasse 2.5 mi
- Port Arthur Historic Site 0.8 mi
- Long Bay Conservation Area 2.1 mi
- Safety Cove State Reserve 2.1 mi
- Eaglehawk Dive Centre 11 mi
Within 12 mi. Some may be missing or closed; marine reserves usually need a permit. Open the map on OpenStreetMap · Missing one? Add it to OpenStreetMap
Sites: © OpenStreetMap contributors (ODbL). Sites and fish: Reef Life Survey / IMOS NRMN, CC BY 4.0; fish names, Wikidata.
How we work out the diving rating
We score every moment of the day, every 10 minutes, from 0 to 10, with simple fixed rules:
- Swell: takes points away based on its height and period (a 10 s swell weighs 50% more than a 6 s one, because it reaches deeper and moves the bottom): nothing under 1.6 ft, up to 6.5 points from 9.8 ft. Surface waves count for getting in and out; we take the worse of the two.
- Wind: takes points away from force 4, about 12 mph (1 point), up to 6 points in a gale; half a point more when it blows offshore, because it pushes surface swimmers away from shore.
- Current: Météo-France's model current takes points away from half a knot (1 point) up to 6 points from 2 knots.
- Slack water: where we show the tide, up to 3 points come off when the water rises or falls fast (mid-tide, especially on spring tides) and none at slack, around each high and low tide.
- Light: half a point more with the sun high (3 hours either side of solar noon), 1.5 less at twilight and 3 less at night. Thunderstorms take away 5 and heavy rain 1.
- Likely visibility: good, fair or poor from the swell of the previous 48 hours, the rain of the previous 72 and the wind of the previous 24. Fair takes 1 point off the day's rating and poor, 2.
- Day's rating: the average of the best window (the stretch of 40 minutes to 3 hours with the best conditions), adjusted for likely visibility.
- Wetsuit, by water temperature: below 50 °F, drysuit; from 50 °F, 7 mm semi-dry; from 57 °F, 7 mm wetsuit; from 64 °F, 5 mm; from 72 °F, 3 mm; from 79 °F, shorty or rash guard.
Today: the best window scores 0 out of 10 and visibility is likely poor, so it takes 2 off.
It's an estimate from the swell, rain and wind of the previous days, not a measurement: real visibility also depends on the bottom, plankton and nearby rivers.
Separately, when there is data, the water clarity the satellite saw in the last few days (NOAA CoastWatch Kd490, 4 km pixels): it does not change the rating.
Slack water comes from the tide: in inlets, channels and between islands the water can keep running for an hour or two after. Ask the local dive shop.
It is a guide built from models, not a guarantee: every site has its own currents and bottom. Look at the water when you get there and ask the dive shop.
Before you get in the water
- Never dive alone: always with a buddy and, if you don't know the site, with a dive shop.
- Check with the local dive shop or club: they know the currents, the no-dive zones and how the water is today.
- Dive within your certification and experience, and stay within depth and no-decompression limits.
- Fly a dive flag (diver-down or alpha flag) on a float and watch for boat traffic.
- Marine reserves need a permit and often have quotas: ask before you go.
- This rating doesn't replace a professional's judgment or what you see when you arrive: if the sea doesn't look right, don't go in.
Questions about diving in Port Arthur
Can you dive in Port Arthur today?
Today isn't a good day (0/10). The best time is 5:30 am to 8:30 am. If you go, go with a dive shop.
What about tomorrow? When's the best time to dive in Port Arthur?
Tomorrow, Friday, October 30: 6:40 pm to 7:30 pm, with a rating of 3/10.
Which day this week is best for diving in Port Arthur?
Wednesday, November 4, at 6/10. Its best time is 5:50 am to 6:30 am.
When is slack water in Port Arthur today?
Today the water barely runs at these times: high tide 12:12 am (11:40 pm–1:00 am), low tide 4:14 am (3:20–5:00 am), high tide 10:42 am (10:20–11:00 am) and low tide 6:27 pm (6:10–6:50 pm). It's an estimate from the tide: in inlets and channels slack water can come later. Ask the local dive shop.
What will the visibility be like in Port Arthur?
Likely poor. Swell (up to 13 ft at 10 s) and wind over the last few days have stirred up the water. Based on the last 24 hours of data. It's an estimate, not a measurement.
What wetsuit do I need to dive in Port Arthur?
Water at 56.7 °F: a 7 mm semi-dry suit, with hood, gloves and booties. If you get cold easily or plan several dives, go thicker.
Can you dive at night?
Yes, with experience, a primary and a backup light, and ideally with a dive shop. Night dive: dark from 8:20 pm. Waning gibbous (89%): a bright night.
How is the rating worked out?
From the swell and its period, the waves, the wind, the current, slack water, daylight and likely visibility. Each factor adds or takes away a fixed number of points and the rating sums up the best window of the day out of 10.
More about Port Arthur today
Learn more
Our own calculation: tide from FES2022 (AVISO/CNES), sun and moon with astronomy-engine, and sea and weather from Open-Meteo (Météo-France, ECMWF, NOAA GFS and Copernicus Marine, CC BY 4.0). Dive sites: © OpenStreetMap contributors (ODbL). FES2022 Tide was produced by LEGOS, NOVELTIS and CLS, funded by CNES, and distributed by AVISO (https://doi.org/10.24400/527896/a01-2024.004), AVISO licence (https://www.aviso.altimetry.fr/fileadmin/documents/data/License_Aviso.pdf). Modified by TidePlanet: constants interpolated from the nearest model cells offshore; heights above mean sea level.