The current account surplus rose 34.6 percent in July from a year earlier to 1.5451 trillion yen, the Finance Ministry said Wednesday.
The rise reflects an increase in exports and a drop in overseas tourism tied to the outbreak of severe acute respiratory syndrome.
July's expansion was a sharp turnaround from June, when the current account surplus shrank 23.5 percent to 1.1006 trillion yen.
The balance of trade in goods and services in July registered a surplus of 734 billion yen, up 67.3 percent from a year earlier, bolstered by a 7.1 percent expansion in the merchandise trade surplus to 970.9 billion yen, the ministry said in a preliminary report.
Exports rose 5.4 percent to 4.398 trillion yen, marking the first gain in two months. Imports grew for the 11th straight month, surging 5 percent to 3.427 trillion yen.
The nation's chronic deficit in the balance of services trade shrank 49.3 percent.