Can Pastilla is a stones throw away from the main airport on Mallorca. It is a mecca for kite surfers and the odd surfer and windsurfer of all levels and abilities. Although there is no particular season, the best times to go are May to September. Although the beach itself gets packed with tourists, there are kite surfing Zones set up. Make sure that you stay within these zones. There is also a kite school with lessons every day, if you are a complete novice and just fancy having a try.
The beach here is long and sandy (about 6kms) so there is enough space to launch and land easily. There is a large sandy area right next to the harbor and this is the surfing zone. The rest of the beach gets rammed with tourists in the summer so it needs to be avoided.
The winds here are nearly always south westerly and they are thermal in nature. The best directions for surfing are south, south westerly, south easterly and south southeasterly. The wind speed averages around 9-10 knots but thermal winds can reach 15 knots in an onshore direction. The water is flat to choppy in the summer with small waves of up to 1 meter in height during the winter. Water temperature here remains between 16-24 degrees depending upon the time of year, so you may want to suit up accordingly.
Along with the surf school, there are eating places along this whole stretch of beach. Surfers and kiters usually meet up in a bar near the launching area. There is also ample parking as well as accommodation and shower/toilet facilities.
Not too much to watch out for except to make sure that you are within your relevant zones and keep an eye out for stray swimmers during the height of the season.