KDDI Corp., Japan's second-biggest mobile-phone operator, reported a third-quarter profit rise of 25 percent as the carrier gained customers.

Net profit climbed to ¥69 billion in the three months to Dec. 31, from ¥55 billion a year earlier, KDDI said Friday. Sales increased 5.5 percent to ¥904.4 billion.

The company raised its full-year operating profit and sales forecasts because mobile-phone users are spending more than it expected. Tokyo-based KDDI's user additions exceeded those at market leader NTT DoCoMo Inc. during the quarter.

Operating profit, or sales minus the cost of goods sold and administrative expenses, increased 40 percent to ¥121.4 billion, the company said.

KDDI expects operating profit of ¥414 billion in the 12 months ending on March 31, 6.2 percent more than its October forecast, while sales are estimated at ¥3.58 trillion, up 2.3 percent from the previous projection.