Bottlenose dolphins are found in Cardigan Bay and the Moray Firth
An annual sea life survey in Wales has recorded a 25% increase in bottlenose dolphin sightings, with the majority spotted off the Ceredigion coast.
The Sea Watch Foundation said most of the mammals were seen near New Quay, Aberystwyth, Mwnt, Ynys Lochtyn, and Aberporth in Cardigan Bay.
The foundation said improved weather conditions this year could explain the rise in bottlenose sightings.
Risso's dolphins, harbour porpoises and minke whales were also seen off Wales.
The Sea Watch Foundation made 354 marine life sightings throughout the British Isles last month and nearly 30% (98) were recorded in Wales.
At least eight species of cetaceans were recorded around Britain and four were found in Welsh waters - the bottlenose dolphin, Risso's dolphins, harbour porpoises and minke whales.
Edita Magileviciute, sightings officer for the Sea Watch Foundation in New Quay, Ceredigion, said: "Compared to the last year we had an increase of bottlenose dolphin sightings by more that 25%, while the number of harbour porpoises remained more or less the same.
"However, more porpoises were sighted in north Wales rather than in west and south Wales. The majority of bottlenose dolphin sightings in west Wales were reported from New Quay, Aberystwyth, Mwnt, Ynys Lochtyn, and Aberporth.
"These places are thought to be favourable feeding areas especially close to the headlands. In north Wales sightings were reported from South Stack, Holyhead and Freshwater Bay in Anglesey.
"In New Quay, where the Sea Watch Foundation's Welsh office is based, we observed bottlenose dolphins almost every day despite rain, fog and gusty winds."
About 140 bottlenose dolphins are thought to live off the Welsh coast.
Dolphin numbers in general have increased steadily since a European Union habitat protection order was placed on Cardigan Bay.