Parks are included: 
Cat Tien is one of Vietnam’s most important and largest National Parks, covering 71,920 Hectares (278 square miles) of lowland and swamp in Southern Vietnam. The Park is home to numerous birds and mammals.  There are many other mammals to see, including: a number of primate species such as the endemic golden-cheeked gibbon, bears, elephant and gaur. Many birds can be found, including such specialities as Germain's peacock pheasant, bar-bellied pitta and the rare endemic orange-necked partridge.
Bach Ma National Park is located in the centre of Vietnam. The park is home to many endemic, rare, precious species. The result of inventory in 2011 shows that there are 69 species listed in the Vietnam Red Book. The typical species are such as Red-shanked Dource langur, Wolf Fire, Binturong, Leopard, Sao la, Truong Son muntjak, Edward pheasant etc. There are 15 endemic species, mainly accounted for 13 bird species such as Lophura nycthemera, Lophura Edwards, Arborophila merlini, Arborophila rufoguralis,… 
Cuc Phuong National Park is situated in the North of Vietnam. Within the 659 vertebrate animal species identified at Cuc Phuong, endangered and rare species include Delacour’s langur (Trachipythecus delacouri), Clouded Leopard (Neofelis nebulosa), Serrow (Carpicornis sumatraensis), cá Niếc Hang (Silurus cucphuongensis) and the red-bellied squirrel (Callosciurus erythraeus cucphuongensis) etc
Best time to go: 
Due to changeable weather condition from South to North Vietnam, not perfect, but March to July can be the best time to combine these three parks.