Offshore banking and opening an offshore bank account in Panama is easier than it sounds, but not as simple as it used to be.
Many Panama banks do open non-resident bank accounts for foreigners, but if you don't live in the country it's a bit more difficult and can take a relatively long time (several weeks or even months). Typical account opening requirements for non-residents include two bank references from your home country, as well as two professional references and two personal references, preferably from within Panama.
You can contact Panama banks directly, but things often move more smoothly if you go through a lawyer or an existing client of the bank who can introduce you to an account representative.
Wire transfers are the same at all Panama banks, as are the fees (because they're regulated by a national board). And, they're high, whether sending or receiving.
SWIFT transactions all go through US banks, the difference is that the biggest banks will use an intermediary of the same name (e.g., HSBC), even though it is technically a separate bank. Others will use other US banks as intermediaries.