I'm not aware of any "open return" tickets but most airlines will sell a fully flexible ticket which will allow changes at a later date at either no or minimal fee.

These tickets are normally very expensive and the alternative would be to buy a cheaper ticket and pay the rees/fare difference charges that apply if or when you want to change it but the amount will not be known until you come to do it.

The flexibility you are looking for comes at a price.

Some countries, and I'm not sure about Peru have as an immigration requirement that you have a flight scheduled out before your tourist visa expires.

Peru has a maximum duration of 183 days on a tourist visa. They do usually require you to have a return or onward ticket, but I'm not sure if they care about what the dates are on it.

Since the time of electronic tickets, open returns are not allowed worldwide.

Earlier (about 8-10yrs) ago there use to be paper tickets, back then it was possible. But not anymore.

Because of the work I do, I often know when I'm going, but have no clue to when I'm returning.

My travels have included Peru. What I do is just buy the best deal I can find on a round trip fair, putting the return date somewhere close to when I think I may return. Then when I know for a fact I'm leaving, I just change the ticket. As a general rule it costs $150 to change the ticket, and the fare change has been any where from $0 to $125.

The only danger is if you stay for over a year, like I did once, then you loose the return ticket.

Thanks everyone, so what I need is an Air France or KLM return ticket to Peru, with the possibility of changing the return date for an amount of money, right ?

Yes. For a fee or for free.

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