Scotland head coach Gregor Townsend hopes his side's Test matches against South Africa and New Zealand can be rescheduled for later this year.
The Scots were due to play a two-match series against world champions South Africa before facing the All Blacks in a one-off game in July.
However, the tour is set to be cancelled because of coronavirus.
"To take on South Africa in a two-match Test series doesn't come around very often," Townsend said.
"The fact they are world champions made it even more special. To go on from those two games to play New Zealand - who we've not played away from home since 2000 - would have made it the best, toughest, most challenging tour I can ever remember.
"I know our players would be better for the experience. It's unlikely we'll have that experience now. Maybe later in the year we'll still be able to play some if not all those games, but we'll see."
Townsend said disappointment over the tour disruption pales into insignificance when viewed against the impact of the Covid-19 pandemic.
Scotland were unable to complete their Six Nations campaign after their final match against Wales in Cardiff was called off 24 hours before kick-off.
Townsend's side had bounced back from two defeats by Ireland and England to register wins over Italy and France, and the head coach admits it was frustrating not to be able to continue the momentum built up from those victories.
"We were on the bus to the Principality Stadium on the Friday afternoon and we got the call to say the game was off and that was our Six Nations over. So there's slight frustration there, but we got four games so 80% of our games were concluded and we saw progression throughout the campaign.
"We had a couple of close defeats and then a couple of victories, so there was momentum that had been created. The players were playing better the more they got to play with each other.
"We'll take the positives out of that and when we get the opportunity to play again - I'd imagine that's going to be on the back of players getting back to club rugby and seeing how they're playing - we know we've got a lot of positives to build on."
The fallout between Townsend and star fly-half Finn Russell cast a huge shadow over the Six Nations campaign. Russell missed the championship after a breach of team protocol led to a suspension and then departure from the camp.
Russell has stated in interviews in recent weeks that relations between the two have improved, and Townsend confirmed he is in regular contact with the Racing 92 player.
"We talked during the Six Nations and we talked after the Six Nations, and we have been in regular contact during lockdown," Townsend said.
"Players and coaches sometimes don't have relationships that are the same all the way through. I suppose it's like being in a family - you have highs and lows, you have periods when you don't understand them and they don't understand you.
"But the important thing is we leave the door open for players and we make an effort to connect and build relationships with all of our players. We want everybody available to us.
"We are gutted if a player is injured and misses the chance to play and we certainly want everyone engaged, available and keen to play for Scotland. It's a massive thing in their lives and I'm sure Finn is really keen to be available and playing for Scotland, as are we with him.
"I am obviously keen to have good relationships and open relationships with all the players I work with."