The hotline service is available in two languages: Press 9 for English, and 8 for Chinese.
Tourists can use the hotline to ask for support on their phone usage as well as general tourist information.
"Dtac would like to offer condolences for those who are affected by the explosion at Ratchaprasong intersection, and would like to offer support to officers and volunteers on duty. Dtac encourages everyone to follow news updates from reliable sources and use the highest precaution when receiving new information," it said in a statement.