Bundala National Park is an internationally important wintering ground for migratory water birds in Sri Lanka.

The vegetation mainly consists of Acacia scrubs including Dichrostachys cinerea, Randia dumetorum, Ziziphus sp., Gymnosporia emarginata, Carissa spinarum, Capparis zeylanica and Cassia spp.

The trees of the forest are Bauhinia racemosa, Salvadora persica, Drypetes sepiaria, Manilkara hexandra (Palu in Sinhalese), and less common Chloroxylon swietenia, Azadirachta indica, and Feronia limonia.

In the small degraded patch of mangrove found at the Bundala lagoon area, Lumnitzera racemosa trees are widespread.

The Bundala National Park has been identified as an outstanding Important Bird Area in the South Indian and Sri Lankan wetlands.

National Bird Ringing Programme (NBRP) was launched in Bundala by in collaboration of Department of Wildlife Conservation and Field Ornithology Group of Sri Lanka in 2005.

[11] The greater flamingo Phoenicopterus roseus which visits in large flocks of over 1,000 individuals, from Rann of Kutch of India is being the highlight.

Black-necked stork Ephippiorhynchus asiaticus, lesser adjutant Leptoptilos javanicus and Eurasian coot Fulica atra are rare birds inhabit in the national park.

[6] Other mammals seen in the park are toque macaque Macaca sinica, common langur Presbytis entellus, jackal Canis aureus, leopard Panthera pardus, fishing cat Felis viverrinus, rusty-spotted cat Felis rubiginosa, mongoose Herpestes spp., wild boar Sus scrofa, mouse deer Tragulus meminna, Indian muntjac Muntiacus muntjak, spotted deer Cervus axis, sambar C. Unicolor, black-naped hare Lepus nigricollis, Indian pangolin Manis crassicaudata, and porcupine Hystrix indica.

[6] The adjacent seashore of Bundala is a breeding ground for all five species of globally endangered sea turtles that migrate to Sri Lanka.

The seeds of the Opuntia cactuses (called kathu potak in Sinhala) are spread by macaque monkeys, and perhaps other animals and birds, that eat the fruits.

The proposed conservation measures are re-demarcation of the park's boundary and widen the boundary to include the northern scrubland, resettle families inhabiting within the park, a programme to control spread of invasive alien plants, create irrigation structures to stop the flow of irrigation water and management of livestock grazing.