Wales and Scotland internationals based in England will be available for all pre-World Cup training after changes to World Rugby's insurance policy.
Premiership clubs had threatened not to release players because of World Rugby's "false and unfair" regulations.
But World Rugby has increased the compensation if a player is seriously injured on international duty.
It means the likes of Wales' Dan Biggar and Scotland's Sean Maitland will be released for camps.
Premiership Rugby stated in December that unless changes were made they would only release players under World Rugby Regulation 9. This would stop some players from linking up with their international side until as late as mid-August.
However World Rugby has more than doubled the compensation from £225,000 to £500,000.
The clubs' threat did not apply to England internationals, who are covered under the agreement between Premiership Rugby and the Rugby Football Union.
"This announcement is more than a regulatory change, it is a statement of commitment to players, unions and clubs," said World Rugby chairman Sir Bill Beaumont.
The insurance changes were approved at Wednesday's World Rugby Council meeting in Dublin, where the proposed Nations Championship was also discussed.
Following a period of due diligence, the cash guarantee offered by sports marketing giants Infront has been increased from £5bn to £6bn, which World Rugby hopes will convince unions to commit to the new concept.
Sources also feel progress has been made over the divisive issue of promotion and relegation.
Talks will continue, with a final decision expected in June.