Soldiers and police rushed to the Tan Yong Mat Railway Station where two bombs exploded, one behind and another in front of the Ra-ngae district railway station at 12.15pm and shortly after.
The bombs were inside lubricant cans placed inside trash bins officials said.
A third bomb exploded behind the Bank for Agriculture and Cooperatives in the district.
The authorities found a fourth bomb near a waterway close to the bank, but were able to disengage it.
Officials said they believed bombs planted by insurgents on Sunday were meant to create disturbances before the Muslim fasting month of Ramadan ends on July 27.