First, check for your self.
Turkey is requiring a "Health Certificate" to enter. It's not much to apply for but costs about 50 euro. Basically your name, citizenship and passport number.
So, I an transiting through Turkey one week, returning the next week and staying a few days, then leaving and returning 3 weeks later. So, not thinking I got the Health Certificate for the date of the first stay. Then it occurred to me that maybe I ought to get one for the transit and one for the second stay. So I went back to the website, filled it out and hit submit. Wouldn't take it. Said I already had one. But they provided an email address for questions. I sent the question do I need one for the transit and for the second stay. They responded! Simply I needed one for the second stay. Didn't say yes or no on the transit and didn't tell me how to get the second one. I am guessing I have to burn the first one before i can apply for the second stay. I wrote again for more detail.
But I think this means applying on line once over there.
Also, that's just the application. In return you get an email that says the certificate will be emailed to you about 48 hours prior to arrival.
Two points here. First their system is a bit difficult because you cant just get them all at once and second, you will need a phone or a computer to receive them once over there unless its your first stop.
Just a heads up.