How can I avoid the inter-bank exchange rate when transferring a large sum from Chile (CLP) to Canada (CAD)?

As a Brazilian I've used Transfer Wise to send money between different countries and currencies. Another option was Remessa Online, but I'm afraid this is specific to the Brazilian market. I've used those to send BRL to the Netherlands as EUR.

Transfer Wise has better exchange rates than most traditional banks and lower extra fees.

If you can establish accounts on cryptocurrency exchanges in source and destination countries, this may be the best way to move a large sum across international borders, in terms of reducing fees. The exact fees will depend on the specific exchanges where you open accounts.

You could take advantage of the volatility compared to government-issued currencies and stand to gain (or lose!) due to value fluctuations while the funds are in cryptocurrency form, or you could buy a "stablecoin" which is fixed to a government-issued currency like USD or CAD (stablecoins exist for both; whether a CAD stablecoin will be listed on whatever exchange you can connect to your Chilean bank is a different question).

Lol, usually people are trying to get the IB rate, because it is minimal for major currencies, lets say EUR USD might be 1.19999 and 1.20001 and yes, some entities may by agreement trade without that "fee" at 1.2 exactly that would also be the published rate you see in print and internet services. The 2.5% you've been quoted is unlikely to be "fixed" by the markets, but the specific desk you asked might only feel comfortable taking the Chilean risk for that kind of money, just like my local Forex shop wants 10% to convert CLP, yes, 10%, just checked! That 10% covers their profit, their risk, and probably the 2.5% of the bank they will have to use. So yeah, you're kinda stuck with looking around for cheaper providers that might offer you something closer to the "true" IB, which should be under 1% unless Chile is in Venezuela-style crisis. Converting up and down to crypto will not work usually to under 1%, in fact most people end up paying up to 5% when zigzagging with crypto. But you may get lucky and convert CLP in Chile to stablecoin, there is TrueCAD(TCAD) among other options, and stablecoins you can usually exit with 0 or close to 0 fees. It is similar to finding an expat or two, because the expat would also be able to acquire TrueCAD at 0 cost. Failing that, Transferwise and its digital competitors should be cheaper than any traditional bank or FX business. I see Coinbase and Coinmama operate in Chile, they are not the cheapest but should be better for TrueCAD than 2.5% . And of course check with trusttoken.com that they wouldn't object to your kinds of amounts, banks etc.