SAS made a net loss of 502 million kronor ($68 million) in the April-June quarter, compared with a loss of 1.05 billion kronor a year earlier.
The Stockholm-based company said that it would have posted a profit of more than 400 million kronor if the ash cloud had not paralyzed air travel across Europe in April.
Revenue was 9.98 billion kronor, down from 12.2 billion kronor in the second quarter of last year.
The airport closures caused by the ash have left their mark in the quarterly reports of several European airlines, including British Airways and Lufthansa.
SAS said it remains focused on a cost-cutting program that has helped it achieve savings of 5.6 billion kronor in the past year and a half.
"During the first six months, we lowered unit cost by 6.7 percent, despite reduced capacity and the major disruptions to services," said CEO Mats Jansson, who announced last week he would leave the company in the autumn after four years in charge.
Shares in SAS rose by 3.45 percent to 27.0 Swedish kronor ($3.68) in early Stockholm trading.
The airline has shed thousands of jobs and sold subsidiary airlines as part of a new strategy to streamline its operations and focus on the Nordic market. However, in the first half of the year SAS said it had noted a record high load factor on primarily intercontinental flights.
"Accordingly, we will now reintroduce one long-haul aircraft that will increase the number of departures to Asia and the US and, in Scandinavia, we will increase the frequency of services between the capital cities already in September," Jansson said.
