* Q4 profit 26.19 mln rials vs 29.2 mln yr ago
* Revenue 116 mln rials vs 119.5 mln
By Matt Smith
DUBAI, Feb 12 - Oman Telecommunications (Omantel) reported a 10 percent fall in fourth-quarter profit on Tuesday, missing analysts' estimates as revenue from text messages and international calls declined.
The former monopoly's profit drop follows a prolonged slump at smaller rival Nawras, a unit of Qatar Telecom (Qtel), as Internet-based services including instant messaging and Voice-Over-IP phone (VoIP) calls hurt margins.
This trend, while global, is more pronounced among Gulf telecoms companies due to the region's large expatriate population, which is increasingly shifting away from conventional calls and texts to contact home.
Omantel made a net profit of 26.19 million rials ($68.03 million) in the three months to Dec. 31, down from 29.2 million rials in the year-earlier period, according to Reuters calculations.
Analysts polled by Reuters on average forecast Omantel would make a quarterly profit of 29.31 million rials.
Omantel said market conditions were "challenging", adding revenue from international calls and text messages had fallen.
Fourth-quarter revenue was 116 million rials. This compares with 119.5 million rials a year ago.
The company also owns a controlling stake in Pakistan's Worldcall.
Omantel's full-year net profit was 116.2 million rials, up from 111.61 million rials in 2011.
The group's customer base was 3.83 million at 2012-end, up 8.5 percent from a year earlier.
($1 = 0.3850 Omani rials) (Reporting by Matt Smith; Editing by Erica Billingham)