Plan kashrut; do not improvise it on the road
Sri Lanka is not a destination where a kosher restaurant appears on every corner. If you keep kosher or Shabbat, build it into the itinerary: weekday meals, Shabbat, and whether you need a kitchenette. Confirmation in advance matters more than a generic list.
Chabad on the island — from official sites we opened
The Chabad Sri Lanka site says the network has existed for about 23 years, that it serves Jewish travellers, and that four houses currently operate. The same page lists addresses in Colombo, Ella, Weligama, Arugam Bay and Hiriketiya (New Tangalle Road, Dikwella), and mentions Shabbat meals, prayers, a synagogue, a mikveh and kosher food.
Chabad of Colombo describes a kosher restaurant from 09:00 to 21:00, deliveries in the Colombo area, and Shabbat and festival meals. It also warns that the house is not open continuously, and that visitors should make contact before arriving. We do not repeat phone numbers or lodging prices here, because they change; get current details from the house itself.
A private kosher tour, not a last-minute search
Elephant Tours describes itself as one of the Sri Lanka companies that specialise in kosher trips: private itineraries for observant travellers, with kitchenette lodging, kosher meals ordered in advance, and routes planned around Shabbat. To start planning, use their tour-planning contact form and say clearly that you need kosher meals and Shabbat arrangements. Booking and payment are with the tour company, not through this investment site.