Europe's waters have never been this warm. Sea-surface temperatures between June and August averaged 21.6C, the highest in 45 years of satellite data, with records broken everywhere from the English Channel to the Mediterranean. A buoy off Mallorca even logged 33.02C in early August, the hottest reading ever recorded by Spain's port authority network.
No region strayed further from normal than the Bay of Biscay, the Atlantic bay along France's and Spain's coasts. Its famously cool water averaged 21.4C over the summer — more than 2.4C above the 1991-2020 average — and by late August it had clocked 186 marine heatwave days this year, compared with a handful per year back in the 1980s. The upshot for holidaymakers: the cold-swim escape that drew Spaniards to San Sebastian, as immortalised in Hemingway's 1926 novel "The Sun Also Rises", has effectively moved west. A marine ecologist at the University of Oviedo says you now need to head to the far corner of Galicia to find genuinely chilly water.
The ecological fallout is striking. Around 95% of the large brown kelp forests on the Asturian coast have vanished since 2010, taking lobster, crayfish and sea urchins with them. Local fishermen are now working with scientists to replant kelp seedlings grown in labs, scattering seeded stones into the waters off Ribeira in Galicia.
Meanwhile, warm-water newcomers are rewriting the menu. More than 1,000 non-native species have entered the Mediterranean, many via the Suez Canal. In August, a swarm of jellyfish clogged the cooling system of France's Gravelines nuclear plant and shut down its reactors — the second time in two years. And on England's south coast, common octopus has gone from rarity to bounty: landings were under 30 tons a year before 2025, but topped 2,600 tons last year and passed 3,000 by late 2026. Great news for Brixham fish merchants with eager southern European buyers; less so for crab and lobster fishermen, one of whose cooperatives calls 2026 an "octopus apocalypse". Four of its 90-odd vessels have gone out of business in a year.
For travellers, this matters more than it might seem. The seaside holidays Europe has long taken for granted — cool Atlantic swims, kelp-fed shellfish platters, familiar catch-of-the-day menus — are shifting in real time. A trip to Spain's northern coast now offers a front-row view of that change, and Galicia's windswept beaches remain one of the last reliably cool swim spots on the Atlantic fringe. It's also a good moment to eat and travel with the ecosystem in mind: choosing local, seasonal seafood in places like Devon or Asturias supports the fishing communities absorbing the shock first.
If anything, the summer is a reminder that Europe's coasts are destinations in flux — worth visiting now, and worth treading lightly in.
Reporting by Reuters, via Daily Sabah Travel.
