Ireland
Best Time to Dive in Ireland
55.39°N 7.38°W
Go June. Conditions are at their best and the basking shark season is on.
- Best time
- Jun
- Water
- 9–15 °C
- Visibility
- 0–15 m
- Season runs
- Mar–Sep
- Dived from
- day boat
- Tidal range
- 1.5–3.5 m
- Species logged
- 8
Worth knowing: 45% of days see seas over 1.5 m.
Where it is
111 km across · coastline from Natural Earth 10m
Diving in Ireland — 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 | Poor | Poor | Poor | Poor | Good | Excellent | Good | Excellent | Good | Poor | Poor | Poor |
| Water temp (°C) | 9 | 9 | 9 | 9 | 11 | 13 | 14 | 15 | 15 | 13 | 12 | 10 |
| Visibility (m) | — | 0–10 | 0–10 | 5–15 | 5–15 | 5–15 | 5–15 | 5–15 | 5–15 | 0–10 | — | — |
| Marine life | Steady | Steady | Steady | Steady | Busy | Peak | Busy | Peak | Busy | Steady | Steady | Steady |
| Best time | Peak |
Excellent Good Moderate PoorPeak season Jun
Long-term averages, 2016–2025. Visibility is estimated from satellite chlorophyll-a. Water temperature is the surface mean; it is cooler at depth.
The Ireland diving season
May to September · Peak season
5 monthsJFMAMJJASOND
- Water temperature
- 11–15 °C
- Visibility
- 5–15 m
- Rain
- 20 days a month
Diving conditionsThe wind eases.
Marine lifeBasking shark (near-guaranteed), Grey seal (likely), Ocean sunfish (hit-or-miss), Blue shark (hit-or-miss) peak at Ireland in these months.
October to April · Off season
7 monthsJFMAMJJASOND
- Water temperature
- 9–13 °C
- Visibility
- under 10 m
- Rain
- 19 days a month
Diving conditionsThe wind is up.
- Spring tides run 3.5 m against 1.5 m on neaps, so currents build around the full and new moon.
- Water temperature is satellite sea-surface temperature, so expect it cooler below the thermocline.
- Visibility is estimated from satellite chlorophyll-a.
Ireland water temperature and weather
746 underwater observation records · 30 surveyed years of ocean data · 10 years of sea temperature
Water & weather
Ireland water temperature by month
The dashed line is the monthly average. Eight days in ten fall inside the band.
10th to 90th percentile rangemonthly mean
17
rough days a month
Seas top 1.5 m on 58% of days. Enough to cancel a day boat
4
blowy days a month
Gusts over 40 km/h, about where a day boat stays in port
19
wet days a month
3 of them bring heavy rain
| Month | Swell | Gusts over 40 km/h | Wet days | Heavy rain | Air | Daylight |
|---|---|---|---|---|---|---|
| January | 4.3 m | 24% | 20 | 5 | 8 °C | 7.4 h |
| February | 4.6 m | 27% | 19 | 3 | 8 °C | 9.3 h |
| March | 3.7 m | 14% | 18 | 2 | 10 °C | 11.5 h |
| April | 2.3 m | 7% | 16 | 3 | 11 °C | 13.9 h |
| May | 2.3 m | 4% | 16 | 2 | 14 °C | 15.9 h |
| June | 2.5 m | 4% | 20 | 3 | 16 °C | 17.2 h |
| July | 2.1 m | 2% | 21 | 4 | 17 °C | 16.6 h |
| August | 2.5 m | 3% | 23 | 3 | 17 °C | 14.8 h |
| September | 2.9 m | 9% | 20 | 3 | 16 °C | 12.4 h |
| October | 3.2 m | 14% | 20 | 5 | 13 °C | 10.1 h |
| November | 3.1 m | 16% | 19 | 3 | 10 °C | 8.0 h |
| December | 4.0 m | 24% | 21 | 4 | 9 °C | 6.8 h |
Swell is the rough end of the month: nine days in ten come in under it. Sea temperature covers 10 years, waves 4.
Pick your week
48 weeks from the daily record. Darker is better, against this site's own year. Pick a month for the detail.
| Week 1 | January week 1: Poor | February week 1: Poor | March week 1: Poor | April week 1: Poor | May week 1: Good | June week 1: Good | July week 1: Moderate | August week 1: Good | September week 1: Good | October week 1: Poor | November week 1: Poor | December week 1: Poor |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Week 2 | January week 2: Poor | February week 2: Poor | March week 2: Poor | April week 2: Poor | May week 2: Good | June week 2: Good | July week 2: Good | August week 2: Excellent | September week 2: Moderate | October week 2: Poor | November week 2: Poor | December week 2: Poor |
| Week 3 | January week 3: Poor | February week 3: Poor | March week 3: Poor | April week 3: Moderate | May week 3: Excellent | June week 3: Good | July week 3: Good | August week 3: Good | September week 3: Moderate | October week 3: Poor | November week 3: Poor | December week 3: Poor |
| Week 4 | January week 4: Poor | February week 4: Poor | March week 4: Poor | April week 4: Moderate | May week 4: Moderate | June week 4: Good | July week 4: Good | August week 4: Good | September week 4: Moderate | October week 4: Poor | November week 4: Poor | December week 4: Poor |
Excellent Good Moderate PoorBest week to go: third of June
January, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Poor | 10 °C | 4.0 m | 31 km/h | 65% |
| Week 2 | Poor | 9 °C | 4.2 m | 31 km/h | 64% |
| Week 3 | Poor | 9 °C | 4.2 m | 31 km/h | 63% |
| Week 4 | Poor | 9 °C | 4.8 m | 34 km/h | 69% |
February, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Poor | 9 °C | 5.0 m | 35 km/h | 68% |
| Week 2 | Poor | 9 °C | 4.4 m | 34 km/h | 66% |
| Week 3 | Poor | 9 °C | 4.4 m | 35 km/h | 67% |
| Week 4 | Poor | 9 °C | 4.5 m | 33 km/h | 60% |
March, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Poor | 9 °C | 3.9 m | 29 km/h | 54% |
| Week 2 | Poor | 9 °C | 3.3 m | 30 km/h | 63% |
| Week 3 | Poor | 9 °C | 3.6 m | 29 km/h | 61% |
| Week 4 | Poor | 9 °C | 3.4 m | 26 km/h | 54% |
April, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Poor | 9 °C | 2.5 m | 26 km/h | 55% |
| Week 2 | Poor | 9 °C | 2.5 m | 26 km/h | 55% |
| Week 3 | Moderate | 9 °C | 2.3 m | 24 km/h | 45% |
| Week 4 | Moderate | 10 °C | 2.0 m | 23 km/h | 46% |
May, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Good | 10 °C | 1.9 m | 22 km/h | 52% |
| Week 2 | Good | 11 °C | 2.2 m | 22 km/h | 50% |
| Week 3 | Excellent | 11 °C | 2.5 m | 22 km/h | 56% |
| Week 4 | Moderate | 12 °C | 2.8 m | 22 km/h | 56% |
June, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Good | 12 °C | 2.8 m | 22 km/h | 57% |
| Week 2 | Good | 13 °C | 2.6 m | 23 km/h | 66% |
| Week 3 | Good | 13 °C | 2.1 m | 23 km/h | 67% |
| Week 4 | Good | 13 °C | 2.4 m | 23 km/h | 68% |
July, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Moderate | 14 °C | 2.6 m | 23 km/h | 71% |
| Week 2 | Good | 14 °C | 2.0 m | 22 km/h | 68% |
| Week 3 | Good | 15 °C | 1.7 m | 22 km/h | 64% |
| Week 4 | Good | 15 °C | 2.0 m | 22 km/h | 70% |
August, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Good | 15 °C | 2.2 m | 24 km/h | 78% |
| Week 2 | Excellent | 15 °C | 2.4 m | 25 km/h | 74% |
| Week 3 | Good | 15 °C | 2.8 m | 25 km/h | 74% |
| Week 4 | Good | 15 °C | 2.6 m | 24 km/h | 68% |
September, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Good | 15 °C | 2.4 m | 25 km/h | 64% |
| Week 2 | Moderate | 15 °C | 2.8 m | 26 km/h | 72% |
| Week 3 | Moderate | 15 °C | 3.0 m | 26 km/h | 67% |
| Week 4 | Moderate | 14 °C | 3.2 m | 29 km/h | 65% |
October, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Poor | 14 °C | 3.5 m | 32 km/h | 70% |
| Week 2 | Poor | 14 °C | 3.4 m | 30 km/h | 64% |
| Week 3 | Poor | 13 °C | 3.1 m | 29 km/h | 61% |
| Week 4 | Poor | 13 °C | 3.1 m | 30 km/h | 65% |
November, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Poor | 13 °C | 2.9 m | 28 km/h | 65% |
| Week 2 | Poor | 12 °C | 2.8 m | 29 km/h | 65% |
| Week 3 | Poor | 12 °C | 3.2 m | 31 km/h | 65% |
| Week 4 | Poor | 11 °C | 3.6 m | 28 km/h | 60% |
December, week by week
| Week | Conditions | Water | Swell | Wind | Rain chance |
|---|---|---|---|---|---|
| Week 1 | Poor | 11 °C | 3.8 m | 29 km/h | 63% |
| Week 2 | Poor | 11 °C | 3.9 m | 31 km/h | 71% |
| Week 3 | Poor | 10 °C | 4.4 m | 32 km/h | 67% |
| Week 4 | Poor | 10 °C | 4.1 m | 32 km/h | 66% |
10 years of daily records, averaged into weeks.
Gear & storms
What to wear
Off the coldest water of each month, not the average — that is what the suit has to cope with.
| January | February | March | April | May | June | July | August | September | October | November | December | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Suit | January: dry | February: dry | March: dry | April: dry | May: dry | June: dry | July: 7 mm | August: 7 mm | September: 7 mm | October: dry | November: dry | December: dry |
- Oct–Jundrysuit
- Jul–Sep7 mm semi-dry
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
Ireland marine life — what you'll see diving
| Species | When | Observed window | Reliability | Evidence | Records |
|---|---|---|---|---|---|
| Bottlenose dolphin | All year | Near-guaranteed | 200 | ||
| Basking shark | Jun, Aug | Near-guaranteed | 111 | ||
| Grey seal | Jul, Sep | Likely | 259 | ||
| Ocean sunfish | Aug | Hit-or-miss | 11 | ||
| Blue shark | Jul | Hit-or-miss | 10 | ||
| Minke whale | May–Jul, Dec | Likely | 62 | ||
| Harbour seal | Feb, May, Aug | Likely | 39 | ||
| Common dolphin | Dec–Jan, May, Jul | Likely | 30 |
Peak Present
- 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 Ireland — common questions
- When is the best time to dive Ireland?
- Go June. Conditions are at their best and the basking shark season is on.
- When is the diving season in Ireland?
- The diving season in Ireland runs March to September, and it is at its best June.
- Is the diving in Ireland good for beginners?
- Not really. It is for experienced divers, so it is not a place to learn or to make your first dives after certification.
- How warm is the water in Ireland?
- Between 9 and 15 °C at the surface across the year, coldest in February and warmest in August. It runs cooler below the thermocline.
- What wetsuit do I need in Ireland?
- A drysuit covers the coldest water of the year. In the warmest months a 7 mm semi-dry is enough.
- What is the visibility like in Ireland?
- Roughly 0 to 15 m depending on the month. That is estimated from satellite chlorophyll-a rather than measured in the water.
- What will I see diving Ireland?
- The most consistently recorded species are Bottlenose dolphin (near-guaranteed), Basking shark (near-guaranteed) and Grey seal (likely), from 746 records within 60 km.
- Does Ireland get tropical storms?
- No. None has passed within 250 km in 30 years of records.
- Is there current in Ireland?
- The tide rises and falls 3.5 m around the full and new moon, against 1.5 m in between. How much of that becomes current depends on the shape of the channel.
- When should I avoid Ireland?
- October–April are the weakest months for conditions.
- How do you dive Ireland?
- Mostly from day boats. Trips run through the season, Mar–Sep.