Best Time to Dive in the Lembeh Strait
The reason to dive it is the muck — rhinopias, mimic and blue-ringed octopus, hairy frogfish. It runs all year, so pick your month on the sea and the sky: August to October.
- Best time
- Aug–Oct
- Visibility
- 5–30 m
- Dived from
- day boat
- Tidal range
- 0.6–1.5 m
- Species logged
- 7
Worth knowing: 7 days a month of heavy rain.
Where it is
111 km across · coastline from Natural Earth 10m
Diving in the Lembeh Strait — monthly breakdown
A year of scuba diving conditions at a glance. Hover a month to isolate it.
| January | February | March | April | May | June | July | August | September | October | November | December | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Conditions | Moderate | Excellent | Good | Moderate | Poor | Moderate | Poor | Excellent | Excellent | Good | Moderate | Good |
| Visibility (m) | 10–20 | 5–15 | 10–20 | 5–15 | 10–20 | 10–20 | 10–20 | 5–15 | 5–15 | 10–20 | 5–15 | 20–30 |
| Marine life | Steady | Steady | Steady | Steady | Steady | Steady | Steady | Steady | Steady | Steady | Steady | Steady |
| Best time | Peak | Peak | Peak |
Long-term averages, 2016–2025. Visibility is estimated from satellite chlorophyll-a. Water temperature is the surface mean; it is cooler at depth.
The Lembeh Strait diving season
April to May · Off season
2 months- Visibility
- 5–15 m
- Rain
- 27 days a month
Diving conditionsThe wind eases. The sea is calmer.
June · Shoulder season
1 month- Visibility
- 10–20 m
- Rain
- 25 days a month
Diving conditionsThe wind eases. The sea is calmer.
July · Off season
1 month- Visibility
- 10–20 m
- Rain
- 21 days a month
Diving conditionsThe sea is rougher. The wind eases.
August to March · Peak season
8 months- Rain
- 22 days a month
Diving conditionsSeas are usually flat.
- Water temperature is satellite sea-surface temperature, so expect it cooler below the thermocline.
- Visibility is estimated from satellite chlorophyll-a.
Lembeh Strait water temperature and weather
328 underwater observation records · 19 surveyed years of ocean data · 0 years of sea temperature
Water & weather
| Month | Swell | Gusts over 40 km/h | Wet days | Heavy rain | Air | Daylight |
|---|---|---|---|---|---|---|
| January | 0.9 m | 0% | 24 | 8 | 30 °C | 11.9 h |
| February | 0.9 m | 0% | 23 | 5 | 30 °C | 12.0 h |
| March | 0.8 m | 0% | 25 | 6 | 30 °C | 12.0 h |
| April | 0.7 m | 0% | 26 | 8 | 30 °C | 12.0 h |
| May | 0.8 m | 0% | 28 | 11 | 30 °C | 12.1 h |
| June | 0.8 m | 0% | 25 | 7 | 29 °C | 12.1 h |
| July | 1.2 m | 0% | 21 | 8 | 29 °C | 12.1 h |
| August | 1.1 m | 0% | 17 | 4 | 29 °C | 12.0 h |
| September | 1.1 m | 0% | 16 | 4 | 30 °C | 12.0 h |
| October | 0.8 m | 0% | 21 | 7 | 30 °C | 12.0 h |
| November | 0.5 m | 0% | 27 | 8 | 30 °C | 11.9 h |
| December | 0.6 m | 0% | 26 | 7 | 30 °C | 11.9 h |
Swell is the rough end of the month: nine days in ten come in under it. Sea temperature covers 0 years, waves 4.
Pick your week
Gear & storms
Swell through the year
The rough end of each month — nine days in ten come in under it.
Amber is over 1.5 m.
Tides
Tropical storms
No tropical storm has come within 250 km in 30 years of records. Swell and wind set the season, not cyclones.
- NOAASea surface temperature, from OISST and MUR
- ERA5Wind, waves, rain and air temperature, via Open-Meteo
- OBISMarine species records within 60 km
- IBTrACSTropical cyclone tracks, 1996 to 2025
Lembeh Strait marine life — what you'll see diving
| Species | When | Observed window | Reliability | Evidence | Records |
|---|---|---|---|---|---|
| Bluespotted ribbontail ray | All year | Near-guaranteed | 91 | ||
| Whitetip reef shark | All year | Near-guaranteed | 38 | ||
| Green turtle | All year | Likely | 83 | ||
| Napoleon wrasse | All year | Likely | 47 | ||
| Hawksbill turtle | All year | Likely | 23 | ||
| Bigeye trevally | Oct, Dec | Hit-or-miss | 12 | ||
| Ocellated eagle ray | Nov–Dec | Hit-or-miss | 8 |
- Observed window
- Months with records. Peak is where most of them fall.
- Reliability
- Near-guaranteed in 60% of surveyed years or more
- Likely 30% to 60%
- Hit-or-miss under 30%
- Evidence
- Years it was seen, out of the years anyone surveyed.
- Records
- OBIS sightings within 60 km.
These are sightings people logged, not a full survey of the reef. A species missing from a month may just mean nobody recorded one.
Diving the Lembeh Strait — common questions
- When is the best time to dive the Lembeh Strait?
- The reason to dive it is the muck — rhinopias, mimic and blue-ringed octopus, hairy frogfish. It runs all year, so pick your month on the sea and the sky: August to October.
- When is the diving season at the Lembeh Strait?
- The diving season at the Lembeh Strait runs August to October.
- Is the diving at the Lembeh Strait good for beginners?
- Yes. It suits Open Water divers, so it works for a first trip after certification.
- What is the visibility like at the Lembeh Strait?
- Roughly 5 to 30 m depending on the month. That is estimated from satellite chlorophyll-a rather than measured in the water.
- What will I see diving the Lembeh Strait?
- The most consistently recorded species are Bluespotted ribbontail ray (near-guaranteed), Whitetip reef shark (near-guaranteed) and Green turtle (likely), from 328 records within 60 km.
- Does the Lembeh Strait get tropical storms?
- No. None has passed within 250 km in 30 years of records.
- Is there current at the Lembeh Strait?
- The tide rises and falls 1.5 m around the full and new moon, against 0.6 m in between. How much of that becomes current depends on the shape of the channel.
- When should I avoid the Lembeh Strait?
- May is the weakest month for conditions.
- How do you dive the Lembeh Strait?
- Mostly from day boats. Trips run through the season, Aug–Oct.