Can you combine blue whale watching with a birding trip in Sri Lanka?

Yes, you can. But you have to come in the whale watching season; November to April in Mirissa or June to October in Trincomalee.

The best blue whale watching site in Sri Lanka is Mirissa in the south coast. The whale-watching season in Mirissa--the best time to whale-watch in Mirissa--is from November to April. Other than Blue whales, in Mirissa, there are chances to see Sperm whales and Bryde’s whales as well. In rare occasions, Orca Killer whales also can be seen.   

The second best place for whale watching in Sri Lanka is Trincomalee in the East coast of Sri Lanka. From June to October is the whale watching season in Trincomalee. However, chances of sighting whales in Trincomalee is not as great as in Mirissa.

Also it is bit difficult to get proper boat facilities there. The place is not geared towards whale watching for tourists, as much as Mirissa. But I got to know that some companies in Mirissa are considering providing proper whale watching boat facilities in the near future.