The belated Wanda Diamond League season kicks off in Monaco on Friday after the inaugural season of the World Athletics Continental Tour continued with Tuesday's Paavo Nurmi Games.
And the government's issuing of elite athlete travel exemptions - preventing them from having to quarantine - means fields are studded with UK athletes.
World champion Johnson-Thompson shook off the dust with a 100m hurdles outing in Italy last month and is entered in the high jump competition at the Diamond League event.
A high-class field is headed by Ukranian duo Yuliya Levchenko and Yaroslava Mahuchikh, the 18-year-old who broke the world junior record at last year's World Championships.
Muir opened with her fourth sub-two minute 800m outdoors in four years, clocking 1:59.5 in Trieste behind training partner Jemma Reekie, and goes up to 1000m in Monaco.
The Scot could face long-time rival Faith Kipyegon, 800m world champion Halimah Nakaayi and fellow Brits Reekie and Shelayna Oskan-Clarke.
Adam Gemili, based in Florida with coach Rana Reider, makes the trip to Europe for a 200m race which might feature world champion Noah Lyles.
Pozzi, set for the 110m hurdles, looks in fine fettle and a 13.17 clocking in Turku was his best outdoors since 2017.
Among Brits holding entries are Kyle Langford (800m), Naomi Ogbeta (triple jump), Eilish McColgan (5000m) and Jake Wightman (1500m).
Pole vaulter Holly Bradshaw competed in Finland twice in ten days, posting a best-ever season opener at the Kuortane Games.
The 28-year-old cleared 4.73, a stadium and meeting record, on 1 August meaning she has passed at least 4.70 in every year since 2011.
She followed that up with 4.63 on Tuesday, enough for another meeting record. The height was also cleared by Greece's Nikoleta Kyriakopoulou.
World finalist Jaz Sawyers and Abigail Irozuru finished one-two in the long jump, going out to 6.54 and 6.52 respectively.
Elsewhere, Elliot Giles ran 1:45.46 to finish second behind European silver medallist Andreas Kramer in Monday's Sollentuna Grand Prix in Sweden. Wightman was 0.09 behind in third.
Darryl Neita came away with 11.65 and victory in the 100m and Emily Diamond managed 54.27 in a rusty one-lap return.
"Oh boy," tweeted Diamond. "I know I’m not in the best shape. For me this season is all about going through the motions so next year isn’t an even bigger shock."