The Easter Road side had hoped to have close to 10,000 fans inside the stadium for the home leg of the tie against FC Santa Coloma but in the end were granted fewer than 5,000.
There is optimism, however, that the City of Edinburgh Council will permit the club to welcome a larger crowd for the match with Hibs expecting to hear confirmation one way or another by close of play on Monday, August 2.
The initial 4,700 briefs will be allocated via an opt-in ballot open to 2021/22 season ticket-holders only with a general sale on Monday if there are any tickets remaining.
Hibs said in a statement: “We can confirm a minimum capacity of 4,700 for our UEFA Europa Conference League fixture with HNK Rijeka at Easter Road on Thursday August 5 with all tickets allocated via an opt-in ballot.
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”Until we discover our 'final' capacity, we will proceed to allocate the 4,700 seats that we know are already approved for the visit of HNK Rijeka.
"We are hopeful of getting an exemption for a larger capacity early next week and will inform fans on whether our application has been successful on Monday evening. We thank the City of Edinburgh Council for their support thus far.”
For those unable to attend or unsuccessful in the ballot the club will live stream the match on HibsTV at a cost of £12.99.