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 Bintulu is October and the most expensive month to fly is June. (Average prices, based on 1118 datapoints.)
The best day to arrive at Kuala Lumpur is Friday and it would be best to avoid Monday, as prices are on average 33.62% higher than on Friday. (Average prices, based on 1114 datapoints.)