Extra security measures were in place at the international airports of Kochi, Thiruvananthapuram and Kozhikode following the threat, the director general of police told AFP.
"We are keeping high alert on the airports and surrounding areas since yesterday," Jacob Punnoose said.
The Central Intelligence Bureau, India's main spy agency, received an anonymous call Thursday saying that sympathisers of Sri Lankan separatist group the Liberation Tigers of Tamil Eelam were planning bomb attacks at one of the facilities.
Police have restricted the entry of vehicles and deployed more personnel and bomb squads in the affected areas, Punnoose said
They have also stepped up baggage screening and restricted visitor access, he added.
Sri Lanka's military says it is on the verge of defeating the Tamil Tigers, who have been waging a campaign since 1972 to create a separate Tamil homeland on the Sinhalese-majority island.
Kerala, on the southern tip of India, borders the state of T