In a bid to encourage testing, 17,000 lateral flow test kits will be posted to football fans heading to Glasgow Green.
While the government has not made testing mandatory for access to the fan zone, it has strongly been encouraged by health officials.
The event will also have Covid marshals on site to ask some attendees whether they have taken a test, as well as a mobile testing bus.
The decision comes in the wake of the fan zone opening on Friday and after Scottish Government officials were repeatedly questioned over the decision not to enforce testing for those attending the fan zone or the four Euro 2020 matches being played at Hampden Park.
Linda Bauld, a professor of public health at the University of Edinburgh, had been among medical experts to question the lack of testing, saying last week: “It’s also controversial because when you contrast this with all the other things that are still restricted, it’s hard for some families, communities and sectors to understand the logic.”
Up to 3,000 fans are allowed in the fan zone at any one time, with alcohol only able to be purchased via table service.
Scottish Labour Health spokesperson Jackie Baillie said: “Sending these kits out is a positive development, but it is too little, too late.
“The whole handling of this affair has been chaos from start to finish.
“People really don’t understand the lack of consistency from the Scottish Government.
“Testing should have been mandatory from the start - even making sure everyone who attends gets one misses the point, if it’s not mandatory people may not test themselves.
“It just takes one person to have missed the opportunity to test themselves for Covid to spread.”
Scottish Conservative shadow public health minister Sandesh Gulhane added: “The SNP’s mixed messaging in relation to the fan zone at Glasgow Green has been hugely unhelpful.
“While plans for increased testing are belatedly welcome, questions must be answered as to why they are only sending out testing kits after the event is well underway.
“Parents and businesses have been understandably angry at this event being given the green light while tough restrictions remain on other celebrations and industries.
“With untested fans having already been at the fan zone, this is the SNP Government taking action after the stable door has potentially already been bolted.
“While everyone wants football fans to enjoy themselves, SNP ministers messaging surrounding the fan zone has been increasingly chaotic. To ensure that this event could run as safely as possible, mandatory testing kits should have been sent out to everyone in advance.”
Health secretary Humza Yousaf stressed the fan zone was a "low risk" event after touring the venue on Sunday, along with national clinical director Jason Leitch.
Mr Yousaf said: “I am encouraged to see first-hand all the mitigations in place at the fan zone, which have helped to ensure that it is a low-risk event.
“Supporters can gather here safely in a controlled environment – with necessary physical distancing and hygiene measures in place – to enjoy the football.
“I am also pleased that feedback from fans and staff so far on the arrangements in place – and the atmosphere – has been overwhelmingly positive.
“Ticket holders have already been contacted to emphasise the importance of self-testing.
“It is important to test both before and after the event, so we are now offering test kits to all fans attending to help minimise the risk of transmission.
“Additionally a mobile testing unit will be on site. Anyone with symptoms of Covid-19 or whose receives a positive test result must stay away, self-isolate and book a PCR test.”
Prof Leitch recently warned there must be a "reverse gear" if Glasgow's Euro 2020 fan zone led to a surge in Covid cases.
Glasgow was kept in level three restrictions longer than any other part of Scotland before measures were eased a fortnight before the start of the Euros tournament.