Illas Atlánticas Marine Park — Ons Sector
Galicia · Spain
The Ons Island sector of the Illas Atlánticas National Park protects a spectacular stretch of granite sea floor where submarine channels, caves, and overhangs are packed with filter-feeding life sustained by Atlantic upwelling. Dense aggregations of spider crabs carpet the bottom during their annual mating migrations, while conger eels the thickness of a diver's thigh occupy deep crevices in the cliff base. The park's strict access controls have allowed populations to recover to pre-industrial densities, giving visitors a glimpse of what Galicia's seas looked like before commercial fishing.
Conditions
Depth
5 to 30 m
Open water and up
Current
Usually gentle
Can pick up on the edge
Visibility
15 to 22 m
Clearest in the calm season
Water
12 to 21°C
7mm wetsuit
Month by month
| Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Water (°C) | 12 | 12 | 12 | 13 | 14 | 16 | 17 | 18 | 17 | 16 | 14 | 12 |
| Vis (m) | 5 | 5 | 8 | 8 | 10 | 12 | 15 | 15 | 12 | 10 | 8 | 5 |
| Current | Strong | Strong | Moderate | Moderate | Gentle | Gentle | Gentle | Still | Gentle | Moderate | Moderate | Strong |
Your chances of seeing each animal
Ocellated Lizard
Last confirmed Jul 8, 2026 · 178 records
Almost always
Nearly every dive
European Shag
Last confirmed Jul 8, 2026 · 165 records
Almost always
Nearly every dive
Podarcis lusitanicus
Last confirmed Jul 6, 2026 · 123 records
Almost always
Nearly every dive
European Stonechat
Last confirmed Jul 7, 2026 · 119 records
Almost always
Nearly every dive
Marbled Crab
Last confirmed Jul 5, 2026 · 84 records
Almost always
Nearly every dive
Conger Eel
Last confirmed May 24, 2026 · 63 records
Almost always
Nearly every dive
European Lobster
Last confirmed May 31, 2025 · 3 records
Likely
About 6 in 10 dives
European Spider Crab
Expected
Known here, not yet in recent logs
Gear