Please be aware that Kuala Lumpur has multiple airports and that these results are for all airports serving the city.
The best month to fly between Kuala Lumpur and Phuket is March and the most expensive month to fly is April. (Average prices, based on 6885 datapoints.)
The cheapest airline flying from Kuala Lumpur to Phuket is AirAsia. They are 60% cheaper than MasWings. (Average prices, based on 6893 datapoints.)
The best time to fly is at around 7. (Average prices, based on 7040 datapoints.)