The London rivals will face off in Baku – the capital city of Azerbaijan – on May 29 as the season reaches its thrilling conclusion.
However, both clubs could be taking as few as just 3,000 fans each to the showcase with half of their 6,000 allocations set to be returned unsold.
The cost and difficulty of making the 5,500-mile round trip has discouraged plenty of supporters from going.
UEFA issued a grovelling apology in the wake of Arsenal writing a strongly-worded letter of complaint.
Baku’s Olympic Stadium can hold 68,700 fans, but there are set to be a worrying number of empty seats.
UEFA’s competitions director Giorgio Marchetti said in response to the Gunners’ letter: “An all-English final played by two London teams was not a very predictable event at the time of the appointment.
“This has added significant difficulties to the event logistics. We are really sorry for the problems that your (and Chelsea’s) fans are encountering trying to organise their journey to Baku.
“Our experts are keenly working on this matter with a view to help find cheaper solutions for travelling fans. We would welcome a joint effort with your club in this respect.’
Both clubs have already recruited Thomas Cook to come up with a £979-per-person day-trip to Baku to reduce costs.