The Bangladesh Cricket Board (BCB) had initially announced the T20I squad during the ODI series last Thursday, with Soumya left out of the original selection.
However, the 33-year-old has now been added to the squad without replacing any player.
Soumya has represented Bangladesh in 87 T20 Internationals, scoring 1,462 runs in the format.
The opening T20I will be played at the Zahur Ahmed Chowdhury Stadium on Wednesday, with the remaining two matches of the series also scheduled to be held at the same venue.
Bangladesh head into the T20I series on the back of a historic 2-1 ODI series victory over Australia — their first-ever bilateral ODI series win against the world champions.
After winning the opening two matches, the Tigers came close to completing a whitewash before Australia edged a thrilling final ODI by one wicket.
T20I squad:
Litton Das, Towhid Hridoy, Parvez Hossain Emon, Tanzid Hasan Tamim, Saif Hassan, Shamim Hossain, Nurul Hasan Sohan, Sheikh Mahedi Hasan, Nasum Ahmed, Rishad Hossain, Shoriful Islam, Mustafizur Rahman, Taskin Ahmed, Nahid Rana and Abdul Gaffar.
