Snorkelling and diving from a charter boat in Greece
Greece: snorkel and dive sites by boat, park fees, anchoring rules, sea temperature by month (NOAA) and wetsuit advice. Sourced.
Sea temperature
15.0–25.9 °C
March to August, NOAA 1991–2020
Source: NOAA PSL (NOAA/NCEI OISST v2.1), checked
Warm water (≥24 °C)
July to September
Our threshold on NOAA means
Park fee
Not verified
No fee confirmed
Checked
28 Oct 2026
2 official, 2 secondary
Yes: the Peristera ancient wreck off Alonissos can be dived from May to October with a certified diving centre (Advanced Open Water needed), while at Zakynthos boats must keep out of Laganas Bay Zone A in summer and at least 50 m from Navagio's shore, according to secondary sources. The sea averages 15.0 °C in March and 25.9 °C in August (NOAA, 1991–2020 mean at our reference point); by our rule of thumb July to September are the months at 24 °C or more, when a 3 mm shorty is enough, while March calls for a 7 mm wetsuit, or a drysuit for diving.
Checked 28 Oct 2026 against 2 official and 2 secondary sources; sea temperature from NOAA (sources). Anything we could not confirm is labelled (how to read the labels). Park rules change: check before you go.
Snorkel and dive sites you can reach by charter boat in Greece
| Site | Type | Where | What the source says |
|---|---|---|---|
| Peristera ancient shipwreck (Alonissos underwater museum) | wreck | Alonissos, Northern Sporades | Visits are dives booked with a certified diving centre, May to October, with certified guides, down to 25 m; you need an Advanced Open Water certificate. Non-divers can take a virtual dive at the visitor centre in Patitiri. (Visit Greece (Greek National Tourism Organisation)) |
| National Marine Park of Zakynthos (Laganas Bay) | marine park | South Zakynthos, Ionian Sea | [Secondary source] ARCHELON, a sea-turtle NGO, wrote in 2019 that navigation is completely prohibited in Zone A from 1 May to 31 October and that speed is limited to 6 knots in the rest of the bay (Zones B and C). (ARCHELON (Sea Turtle Protection Society of Greece)) |
| Navagio (Shipwreck) Bay | bay | North-west Zakynthos | [Secondary source] To Vima reported on 2 June 2026 that a Joint Ministerial Decision keeps vessels from approaching or anchoring within 50 m of the shore and bans swimming in the whole cove until 31 October 2026. (To Vima (newspaper)) |
These are the sites we could document from official or labelled sources, not a full list. Fishing is a separate question: fishing rules in Greece.
Sea temperature in Greece by month
The sea is warmest in August (25.9 °C) and coolest in March (15.0 °C). ● marks our warm-water months (24 °C or more): July to September.
| Month | Sea surface (NOAA) | Air (NASA POWER) | Our wetsuit rule of thumb | Catamaran, avg per week (12 Knots) |
|---|---|---|---|---|
| January | 15.9 °C | 10.5 °C | 7 mm wetsuit, or a drysuit for diving | €4,561 |
| February | 15.1 °C | 11.4 °C | 7 mm wetsuit, or a drysuit for diving | €4,545 |
| March | 15.0 °C | 12.8 °C | 7 mm wetsuit, or a drysuit for diving | €4,527 |
| April | 16.2 °C | 15.7 °C | 7 mm wetsuit, or a drysuit for diving | €4,619 |
| May | 18.9 °C | 19.2 °C | 5 mm full wetsuit | €6,435 |
| June | 22.3 °C | 24.3 °C | 3 mm full wetsuit | €8,402 |
| July | 24.5 °C ● | 27.1 °C | 3 mm shorty | €9,336 |
| August | 25.9 °C ● | 27.7 °C | 3 mm shorty | €9,538 |
| September | 24.9 °C ● | 24.1 °C | 3 mm shorty | €8,098 |
| October | 22.8 °C | 20.0 °C | 3 mm full wetsuit | €5,414 |
| November | 20.4 °C | 16.2 °C | 5 mm full wetsuit | €5,114 |
| December | 17.8 °C | 12.5 °C | 7 mm wetsuit, or a drysuit for diving | €5,239 |
Of the months at 24 °C or more, the cheapest on 12 Knots' average weekly catamaran price is September at €8,098 per week (12 Knots, checked 27 Oct 2026), with the sea at 24.9 °C (our comparison).
Sea surface: NOAA OISST v2.1 1991–2020 monthly mean for the 1/4° cell centred on 38.375° N, 20.875° E (Ionian Sea between Meganisi, Ithaca and the mainland) (NOAA PSL (NOAA/NCEI OISST v2.1), checked 28 Oct 2026); the sites above may be warmer or cooler, and shallow bays warm up faster. Air: our 10-year NASA POWER mean at Lefkada (NASA POWER, checked 28 Oct 2026). Prices are asking prices that mix bareboat and crewed listings.
Mooring, anchoring and park rules for your boat
- [Secondary source] Zakynthos: no navigation in Laganas Bay Zone A from 1 May to 31 October; 6-knot limit in Zones B and C (ARCHELON, 2019). (ARCHELON (Sea Turtle Protection Society of Greece))
- [Secondary source] Navagio: no approaching or anchoring within 50 m of the shore and no swimming in the cove, until 31 October 2026 (To Vima, June 2026). (To Vima (newspaper))
Can I scuba dive from the boat? Permits and dive centres
- Peristera: only with a certified diving centre and certified guides, Advanced Open Water or higher. (Visit Greece (Greek National Tourism Organisation))
- [Not verified] The general Greek rules on recreational diving near antiquities and with or without a dive centre: not verified (we did not read the law).
Park and mooring fees
| Fee | Amount | Status | Source |
|---|---|---|---|
| Peristera guided dive | Not verified | not verified | – |
| Zakynthos marine park | Not verified | not verified | – |
Underwater visibility
[Not verified] We found no official or survey source for underwater visibility, so we give no figure. Ask the local dive centre on the day.
What wetsuit do I need in Greece?
From August's 25.9 °C our rule of thumb gives a 3 mm shorty; in March (15.0 °C) a 7 mm wetsuit, or a drysuit for diving. The month-by-month column is in the table above.
Our rule of thumb for snorkelling, applied to the monthly mean: 28 °C or more: swimsuit or rash vest; 26–28 °C: rash vest or 1–2 mm shorty; 24–26 °C: 3 mm shorty; 21–24 °C: 3 mm full wetsuit; 18–21 °C: 5 mm full wetsuit; below 18 °C: 7 mm wetsuit, or a drysuit for diving. Divers lose heat faster and meet cooler water at depth: go one band thicker. People feel cold differently; this is a guide, not a source's advice.
| Mean sea temperature | Our rule of thumb for snorkelling |
|---|---|
| 28 °C or more | swimsuit or rash vest |
| 26–28 °C | rash vest or 1–2 mm shorty |
| 24–26 °C | 3 mm shorty |
| 21–24 °C | 3 mm full wetsuit |
| 18–21 °C | 5 mm full wetsuit |
| Below 18 °C | 7 mm wetsuit, or a drysuit for diving |
See boats in Greece
See catamarans for rent in Greece on SamBoat
Check the park rules above and the boat's own kit (snorkel gear, dinghy, dive-ladder) with the operator before you book; listings and prices on SamBoat are SamBoat's own. We may earn a commission if you book through our links, at no extra cost to you (disclosure).
What we could not verify
- The rules of the National Marine Park of Alonissos and Northern Sporades (its site refused our connection).
- The Zakynthos park's own zoning text (its site refused our connection), and any park fee.
- Greek rules on diving near antiquities and diving without a dive centre.
- The price of a Peristera dive.
- Underwater visibility.
How to read the labels
- [Secondary source]: From a newspaper, NGO, guide or tour operator; not official.
- [Not verified]: We could not confirm it. We leave it open rather than guess.
- No label: Read in an official text: government, park authority, ministry or official tourism board.
Sea temperatures are NOAA's; the wetsuit column, the 24 °C warm-water mark and any sum or comparison are ours and say so. Park rules change and some are seasonal: check with the park, your charter base or a local dive centre before you go.
Sources
- Visit Greece (Greek National Tourism Organisation): Alonnisos underwater museum: the ancient shipwreck of Peristera (official), checked 28 Oct 2026.
- ARCHELON (Sea Turtle Protection Society of Greece): Collisions of boats with sea turtles continue at Zakynthos National Marine Park (secondary, not official), checked 28 Oct 2026.
- To Vima (newspaper): Zakynthos: Navagio beach access curbs extended through 2026 (secondary, not official), checked 28 Oct 2026.
- NOAA PSL (NOAA/NCEI OISST v2.1): NOAA High-resolution Blended Analysis: OISST v2.1 long-term mean monthly sea surface temperature, 1991–2020 (sst.mon.ltm.1991-2020.nc) (official), checked 28 Oct 2026.
- NASA POWER: Prediction Of Worldwide Energy Resources: Monthly API (T2M, WS10M) (official), air temperature, pulled 28 Oct 2026.
- 12 Knots: Catamaran charter in Greece (secondary, prices), checked 27 Oct 2026.
Method: methodology. Data: JSON.
More on Greece
Frequently asked questions
Can you snorkel and dive from a charter boat in Greece?
Yes: the Peristera ancient wreck off Alonissos can be dived from May to October with a certified diving centre (Advanced Open Water needed), while at Zakynthos boats must keep out of Laganas Bay Zone A in summer and at least 50 m from Navagio's shore, according to secondary sources. The sea averages 15.0 °C in March and 25.9 °C in August (NOAA, 1991–2020 mean at our reference point); by our rule of thumb July to September are the months at 24 °C or more, when a 3 mm shorty is enough, while March calls for a 7 mm wetsuit, or a drysuit for diving.
How warm is the sea in Greece?
By NOAA's 1991–2020 averages at our reference point (Ionian Sea between Meganisi, Ithaca and the mainland), the sea surface is warmest in August at 25.9 °C and coolest in March at 15.0 °C. Months at 24 °C or more: July to September.
Do I need a wetsuit to snorkel in Greece?
By our rule of thumb (not a source's advice): a 3 mm shorty in August and a 7 mm wetsuit, or a drysuit for diving in March; divers should go one band thicker.
Do I need a dive centre to scuba dive in Greece?
Peristera: only with a certified diving centre and certified guides, Advanced Open Water or higher. Not verified: The general Greek rules on recreational diving near antiquities and with or without a dive centre: not verified (we did not read the law).
Are there park fees or mooring rules for boats in Greece?
Secondary source: Zakynthos: no navigation in Laganas Bay Zone A from 1 May to 31 October; 6-knot limit in Zones B and C (ARCHELON, 2019). Secondary source: Navagio: no approaching or anchoring within 50 m of the shore and no swimming in the cove, until 31 October 2026 (To Vima, June 2026). Fees: not verified.