The seizures were made since Saturday from near Zemabawk in the outskirts of Aizawl, Spokesman Peter Zohmingthanga said.
While 63 gm of heroin was seized today, 28 gm and 15 gm of heroin were seized separately on Saturday night.
Lalawmpuia, Paukapluni and Lalrengthangi, all from Myanmar and Lalduhkimi, a resident of the state, were arrested.
They were booked under various sections of NDPS Act, the spokesman said.