There are many places where whales, dolphins, whale sharks, stingrays etc. can be seen by a guided boat tour, a snorkel trip or even from the costal line.
The Algarve is a year-round destination with pleasant temps during the winter and hot temps in summer. Anyhow, there is often a breeze in summer. Dolphin tours are offered from March until late November. Although the best months to spot schools of dolphins are from June to September. In spring and at the end of the summer from September onwards it's cold out on the sea in the morning; bring a warm jacket.
Crowds at the Algarve
The Algarve is a popular destination by the Portuguese. They spend their summer holidays here between the end of June until the beginning of September. It's pretty busy and accommodation prices are at a high level. It's almost the same at Easter and Christmas.
Weather at the Algarve
The summer from June to mid-September is quite hot with temps in the high 20s and above while nights are pleasant below 20°C. In spring and fall, the day-temps are between 20°C-25°C and nights are between 10°C-15°C still comfortable for camping. During winter the temps are still lovely below 20°C, but one digit temps in the night. Most precipitation during winter. Summer is almost dry. Rain can occur from autumn to spring, but usually not much.
The whale watching season starts in November until the end of April. The very best months are March and April for blue whale sightings. The sea is calm in the morning and rough in the afternoon. The whale watching tours start very early in the morning between 6 and latest 7. May to October whales can be spotted, but less in number and the sea can be rough. Anyway, booking is possible at low season, give them a call view days in advance. Be aware May, and June is also the worst time of the monsoon.
At the peak season, the chance for sightings is 90 %. We went there in January and spotted one blue whale a couple of times. We got told that they sometimes spot up to eight in one day. Another good option is Trincomalee from June to October with best sightings in August and September.