UPDATE 1-Diamond Offshore's quarterly earnings rise 43 percent

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July 26 (Reuters) - Diamond Offshore Drilling Inc.'s (DO.N) quarterly earnings rose 43 percent, topping analysts' estimates, on continued strength in the demand for its drilling rigs. Second-quarter net income rose to $251.9 million, or $1.81 per share from $175.7 million or $1.27 per share, a year ago. Revenue rose about 27 percent to $648.9 million.

Analysts expected earnings of $1.73 a share on revenue of $647.6 million, according to Reuters Estimates.

The company said international markets for its floater and jack-up equipment remained strong during the quarter. Four of its semisubmersible rigs received commitments that will occupy them into the early part of the next decade.

Higher exploration and production activity, supported by near-record crude oil prices, has increased demand for drilling rigs internationally, pushing up their rent rates.

Rent rates for deepwater and jackup rigs rose from a year ago.

Shares of the company have risen about 38 percent since the beginning of the year, slightly outperforming the S&P Oil & Gas Drilling Sub-Industry Index .GSPOILD, which has gained 33 percent. (Reporting by Gurdeep Singh in Bangalore)