Booking an MA35 appointment, and what it's actually like
MA35 (Vienna's immigration office, formally Magistratsabteilung 35) runs entirely on booked appointments. There are no walk-ins, which is the first thing to take on board, because turning up without a Termin (appointment) means turning around and going home. The better news is that once you actually have an appointment, the experience is calmer and more ordinary than the office's online reputation suggests.
No walk-ins, ever
Every interaction at MA35 starts with a booked Termin (appointment).1 I have watched people get turned away at the door every single time I have gone in to renew, so take the booking seriously. Slots tend to be filled roughly two weeks out, so build that lead time into your planning; this is not usually something you can arrange for tomorrow.
Treat the appointment itself as one of the most important appointments of your life. Do not be late, and clear the whole day for it. Most of the time you will not need the whole day, but the cost of arriving late or rushed is high enough that it is not worth the gamble.
Booking the right slot
MA35 runs different booking pages for different situations, and using the wrong one wastes a slot. First applications, renewals, and EEA cases each have their own page, so book through the one that matches your case.1 First applications go through the third-country-national first-application page. Renewals (extension applications) have their own page, and a renewal can be filed at any of the office's Außenstellen (branch offices), regardless of which district you live in.1 EEA citizens have a separate page again.
First applications are handled at the dedicated first-application centre at Dresdner Straße 93 in the 20th district, while renewals are spread across the branch offices.1 One small but genuinely useful trick that the booking page itself points out: you can compare availability across the different Referate (the office's units) and grab an earlier free slot at a less-busy one.
What the appointment is actually like
Once you are in, the wait is usually short, under twenty minutes in my experience, though it occasionally stretches past an hour.
On language, English will get you all the way through. Your caseworker can run the appointment in English, so you do not need German to complete it. The one real condition is that your English has to be genuinely good enough to follow what is happening, because you are responsible for understanding what you agree to. A little German still earns real goodwill, though. Even scattered words, a Termin here, a Referat there, a danke at the end, land well; the staff are sympathetic that not everyone grew up speaking German, and they notice the effort.
Your documents get scanned at the appointment, and across all my renewals MA35 has never physically lost anything of mine. The office's reputation for losing paperwork deserves a calm correction: realistically, you are more likely to misplace your own documents than they are to lose your scanned file. The channel that genuinely carries risk is mailing documents off, as you may have to for a Visa D for instance, rather than handing them across the counter to be scanned.
If something is missing, what usually follows is an email asking you to supply it, not a fresh appointment. Reaching a human at MA35 any other way is hard. Phone and email sometimes work and often do not, and after the appointment most follow-up runs by email or mail with minimal reply. The appointment is the reliable channel; everything around it is hit and miss.
Paying the fee
Payment is usually handled with a QR code that MA35 mails to you before the appointment, which is the smoothest way to do it. If that is not set up, you can pay at the Kassa (the cashier desk) by cash or card, possibly with a small card surcharge.1
One closing note from experience. The cleaner your packet, the faster the whole thing moves. The one time I cut corners, back in the Visa D days, I got nothing but headaches and repeat rounds. The by-the-book residence application went smoothly and got a fast decision. The results of your application will typically mirror the correctness and completeness you furnish.
Official sources