Stronger domestic demand in France and Germany helped push the economy into growth after the prolonged downturn, the data agency said releasing a flash estimate that is subject to revision as more data becomes available.
The gain follows a 0.2 percent economic decline in the first quarter in the 17-member eurozone and a 0.1 percent decline in the 28-member European Union, which added Croatia to its ranks in July.
The data office on Wednesday said the gross domestic product rose 0.3 percent in both the currency region and the European Union as a whole.
Several members are not included in the flash estimate, including Denmark, Greece, Croatia, Luxembourg, Malta and Slovenia.
But GDP figures from the four largest eurozone economies -- Germany, France, Italy and Spain -- are included, as is a 0.6 percent gain in the quarter posted by Britain, which is not a member or the eurozone.
In Germany, the GDP for the quarter rose 0.7 percent. In France, the economy grew 0.5 percent April through June. Italy posted a 0.2 percent decline in the quarter. Spain's economy slipped 0.1 percent in the reporting period.
Of 21 countries included in the report, 15 posted positive numbers, while six reported a continued contraction.
Portugal posted the fastest expansion with a GDP of 1.1 percent. Portugal was followed by Germany, Finland and the Czech Republic at 0.7 percent.
The low mark was set by Cyprus, where the economy shrank 1.4 percent in the quarter that followed a $13 billion bailout the country accepted to dig its banks out of trouble.
The Netherlands matched Italy with a 0.2 percent decline. In Spain, Bulgaria and Sweden the contraction came to 0.1 percent.