Prakash Darekar (ward 5) and Sukhda Pawar (ward 82) of MNS and Kesarben Patel (ward 73) of Congress joined BJP in presence of BJP Mumbai unit chief Ashish Shelar.
"Those who joined BJP today have expressed their faith in Prine Minister Narendra Modi and Maharashtra Chief Minister Devendra Fadnavis," Shelar told reporters at the party office.
On Tuesday, Suresh Awale, Ghatkopar (East) corporator, deserted MNS to join the Shiv Sena.
MNS expelled two corporators on April 15 for cross-voting in BMC ward committee polls. Later, four more faced action for accepting development funds from BJP and Sena.