A humpback whale was spotted by Jersey schoolchildren returning from a day trip to Sark.
Teachers and pupils from St Lawrence Primary School and d’Auvergne School captured the sighting on video and in photos as they travelled on Monday.
Donna Gicquel de Gruchy, from British Divers Marine Life Rescue Channel Islands, said the humpback whale appeared to be a young one.
She said it was a “very lucky and rare sighting” and she hoped it was a sign of healthy waters.
Two humpback whales were also spotted off the Channel Islands in July last year.
Local wildlife expert Liz Sweet described the recent sightings of the creatures in Guernsey waters as both “very rare” and “very special”.
Ms Sweet said the increase could be down to the whales getting confused.
She said: “There is a massive migration route through the Bay of Biscay and up around the Irish coast as they head to their feeding grounds in the Arctic.
“It is really busy, really noisy water and it is easy for these animals to get a little bit confused, maybe a little bit lost.”
Her other theory was that rising sea temperatures could be luring the whales’ food closer to the Channel Islands.
Ms Sweet explained: “Fish are moving around a lot more so it might have been following food so it could have just been here for a stop off.”