CORRECTED-UPDATE 1-SingTel Q3 underlying profit rises from partly-owned Airtel's strong performance

(Corrects to say underlying profit in HL and lede, not profit; Fixes mobile revenues from Optus in paragraph 5 to A$1.40 billion, not A$1.40 million)

Feb 16 (Reuters) - Singapore Telecommunications on Thursday posted an 18.2% jump in third-quarter underlying profit, driven by stronger performance of its partly-owned Bharti Airtel.

All segments of SingTel's business benefited from a continued recovery in international travel, driving an increase in roaming revenues and higher prepaid customers, while Telkomsel service revenue growth was offset by higher network costs.

Bharti Airtel, India's No.2 telecom carrier by subscribers, reported a bigger-than-expected increase in third-quarter revenue earlier this month, helped by 4G subscriber additions and higher revenue per user.

SingTel, which is Southeast Asia's largest telecom firm, reported underlying net profit of S$559 million ($418.54 million) for the quarter ended Dec. 31, compared with S$473 million a year earlier.

Mobile revenues from Optus, which reported a data breach of up to 10 million customers in October last year, came in at A$1.40 billion ($967.82 million), compared with A$1.32 billion a year earlier. ($1 = 1.3356 Singapore dollars) ($1 = 1.4480 Australian dollars) (Reporting by Jaskiran Singh and Harish Sridharan in Bengaluru; Editing by Shailesh Kuber)