The Boccia International Sports Federation (BISFed) has cancelled the Póvoa World Open because of the coronavirus crisis.
It means that no international competitions are due to be staged before the Tokyo 2020 Paralympics.
There will also have been a gap of almost 18 months between the last BISFed event and the Tokyo Games, owing to the global health crisis.
BISFed said that there were too many safety variables associated with staging an event which were beyond its control and the control of the Póvoa World Open Organising Committee.
It had been hoped that the tournament in Portugal, scheduled to run from July 12 to 19, would offer a warm-up event before the Paralympics, but that is not to be.
Portugal has seen a sharp fall in its coronavirus infection rate since the start of February, but travel restrictions remain in place across much of the world and mass gatherings are hard to organise.
The first three BISFed-sanctioned events of 2021, in France, Spain and Croatia, had already been cancelled due to the global health crisis.