Sea shipping is incredibly efficient which really helps make such surprising things possible with a strong enough comparative advantage. That said, it’s still an added friction, does take time and adds in some more risks. Being close counts for quite a lot if that trade is more or less freely allowed.

Looking at this World Bank data for Denmark in 2023 (latest year it was tabulated for), it actually has next door big neighbor Germany as getting ~13.7% of Denmark’s total exports followed by Sweden, the Netherlands and Norway before getting to the US’ ~5.0%. Somewhat more distant European heavyweights like the UK, Poland and France follow not terribly far behind before you get to enormous economy China. Swap it to import and again neighboring big economy Germany is providing a whopping ~20.3% followed by Sweden and the Netherlands before you get to China’s ~6.5%, then Poland, then the US’ ~4.6%. Not far behind trails Norway at ~4.5%. So Norway has a relatively similar share of Denmark’s trade going either way compared to what the US has, despite having an economy multiple hundreds of times smaller than that of the US. That proximity really helps!

The US in the same data is importing roughly the same ~14% share from each of neighboring Mexico and Canada as well as giant super focused on exporting China, and going the other way US exports are double to both Mexico and Canada what they are to China. Despite the Mexican and Canadian economies even combined together being like a fifth of China’s economy.

Also most of Canada’s population is distributed pretty near to the very lengthy border with the US, intermittently broken up by challenging terrain and only a comparatively small fraction is coastal. This has had the effect of encouraging parallel north-south trade corridors going across the border. If those flows instead are directed east-west to Canada’s ports which are also already stretched then the existing infrastructure can also potentially be limiting even with Canada signing a ton of amazing trade deals. Check out this picture of Canada’s road networks and see that there are some rather surprising bottlenecks.

All that said Canada should absolutely seek the best trade deals it can get with as many countries as possible in the circumstances. But I think it may be difficult to find enough low-hanging fruit still left to make up for such a huge gap, surely if it were that easy to expand trade so massively it wouldn’t have been ignored prior to this point of crisis?