The Kenyan, 26, who won the African 100m title last month, is due to race in the heats on Friday at the global event in Eugene, Oregon.
Omanyala will fly from Kenya at 18:00 local time on Thursday, and is expected to arrive in Eugene less than three hours before the men’s 100m heats begin in the evening session on day one of the World Championships.
However, he will then need to clear United States customs, travel to the arena, pick up his accreditation and find time to warm up before bidding for a place in the semi-finals. According to Omanyala, Athletics Kenya Executive Member, Barnabas Korir, is holding talks with World Athletics about the possibility of staging a solo heat if the sprinter does not arrive on time.
Omanyala is the third-quickest man in the world this season behind Americans, Fred Kerley and Trayvon Bromell, and set the African 100m record of 9.77 seconds in September last year.
Omanyala told the BBC’s Michelle Katami in Nairobi that intervention from authorities in Kenya had helped him secure the much-needed permission to travel.
“I want to thank everybody who has worked around the clock to ensure I get my visa,” he added.
“There’s nobody to blame here. It’s the system, how it works. You cannot force anything.”
Korir said that several other Kenyan athletes had also been affected by visa delays, while Ethiopian and Nigerian athletes are also understood to have encountered issues.
World Athletics said it was working with the Oregon 22 organizing committee and the US Olympic and Paralympic Committee (USOPC) to follow up on visa applications affecting some competitors, but said “the majority have been successfully resolved”.