The reason? All five are participating in a cultural expo in Montreal designed to promote the Nordic countries. No doubt inspired by the attention that a Twitter spat between Sweden and Denmark got back in July, things were taken a step further this week when a five nation Nordic digital fight broke out, with the digs ranging from cheesy to awkward.
A Norwegian brag about floating underwater tunnels kicked off the feud, to which Denmark quickly retorted that cars are old fashioned in bike-friendly Copenhagen anyway.
A string of boasts about renewable energy from Iceland, Denmark and Finland definitely fell on the cheesier side of things, though Finland at least deserves points for effort for their flatulence-based green insult:
Never missing a chance to talk about how happy they are, the Danes fired a (metaphorical) shot at the Swedes for ‘only' being the 10th happiest nation on earth. Denmark's bigger neighbour then quite happily claimed that both they and Iceland are healthier than the bacon-lovers.
Like all awkward arguments, the discussion then turned to war and peace, at which point Sweden served a timely reminder that it will be on the United Nations Security Council next year.
Thankfully things soon got less serious, with Iceland fighting back hard and reminding everyone that they gave the world Of Monsters and Men, Björk and Sigur Ros, before mocking recently retired 27-year-old, Swedish DJ Avicii.
Sweden then had to go and ruin the party by claiming it founded free speech 250 years ago, at which point everyone else seemed to give up, either awed or bored into submission.
As for @Canada, they have yet to get involved.
If you're really keen, some highlights from the great Nordic Twitter war are collated below.