"This acquisition will enhance consumer access ... by improving broadband inclusion in new areas targeting the up-country and non-city areas," Chief Financial Officer Tee Seeumpornroj said in a stock exchange filing.

AIS said it plans to buy Triple T Broadband for 19.5 billion baht and purchase 19% of JASIF for 12.9 billion baht.

The investment plan comes as rival operators True Corporation Pcl and Telenor ASA's Total Access Communication Pcl (DTAC) seek to merge their operations, pending regulatory approval.

The AIS announcement sent Thai telecommunication shares up. AIS gained 2.28% at 0400 GMT, while True and DTAC climbed 0.43% and 1.12%, respectively, compared with a 0.46% decline in the benchmark index. JAISF shares fell 4.7%.

AIS said the transaction is subject to regulatory approval and is expected to be completed in the first quarter next year.

($1 = 35.6500 baht)

(Reporting by Chayut Setboonsarng; Editing by Ed Davies)