The Welsh government says crowds of up to 10,000 will be allowed back at sporting stadiums from Monday, 7 June.
Large outdoor events such as sports matches and organised runs can go ahead for up to 4,000 people when not seated, and 10,000 when seated.
Parkrun events and other organised running groups could also resume.
Wales’ men’s rugby team host Canada on 3 July at the Principality Stadium followed by successive Tests against Argentina on 10 and 17 July.
Glamorgan’s Sophia Gardens home will host a one-day cricket international between England and Pakistan on 8 July, while the Welsh county stage their opening T20 Blast match on 10 June against Gloucestershire.
The new Hundred tournament starts in late July with Cardiff hosting matches for the Welsh Fire men’s and women’s teams.
The Under-20s Six Nations rugby tournament is being hosted in Wales between 19 June and 13 July with five matchdays at Cardiff Arms Park.
In regional rugby, Cardiff Blues’ home match on 5 June against Zebre will be played behind closed doors.
Ospreys host Benetton on 12 June in the Pro14 Rainbow Cup but the region have previously said there will be no spectators at the game.
The fixture has been switched to Bridgend’s Brewery Field from the Liberty Stadium with the Swansea venue being prepared for next season.
Scarlets face Edinburgh in Llanelli on 13 June, while two days later Parc y Scarlets is also the venue for Wales women’s football friendly against Scotland.
Cardiff City, Swansea City, Newport and Wrexham have finished their league seasons while the news of crowds has also come too late for the Cymru Premier domestic campaign.
Chepstow racecourse have four meetings scheduled in June which are currently due to be held behind closed doors.
Welsh Athletics chief executive James Williams tweeted: “Incredibly positive news for the Welsh Athletics RunWales community, we will provide further details once the guidance has been read in full.
“Fingers crossed this will see running events return very soon in Wales.”
The Welsh government said all organisers planning events and activities must complete a risk assessment and also put in place measures to prevent the spread of coronavirus, including social distancing.
So while the 10,000 figure has been stated, the number of spectators in most venues is going to be lower because of Covid-19 rules.
The five-figure crowd will probably only apply to the 74,000 capacity at the Principality Stadium.
There have been a series of pilot tests events which included Swansea and Newport County’s play-off home semi-final matches in May, with 3,000 and 900 fans allowed at Liberty Stadium and Rodney Parade respectively.
Up to 1,000 supporters were allowed at the opening day of Glamorgan’s county championship match against Lancashire on 3 June.
Wales football fans are to return on Saturday, when 6,500 spectators will watch Robert Page’s side at the Cardiff City Stadium as they take on Albania in the final warm-up match before Euro 2020.
First Minster Mark Drakeford said: “The risk of infection is significantly less outdoors than it is indoors. This is why we are phasing in the changes in this three-week cycle.
“This will allow more people to enjoy events outdoors and take advantage of the Welsh summer, while we continue to roll out the vaccination programme to all adults.
“We will review the public health situation again in a couple of weeks to see whether we can continue to relax the restrictions and restart indoor events.”