Meeting new people in Salzburg rarely fails because there are no people. It fails because the first meeting is badly chosen.
Three places that make it easier
Stadt:Bibliothek instead of coffee-interview energy
The Stadt:Bibliothek at Schumacherstraße 14 works well because the Open Library runs from 6:30 a.m. to 10 p.m. every day. You do not need to keep the conversation alive every second.
Haus der Natur if you need something to react to
The Haus der Natur at Museumsplatz 5 is huge, with more than 7000 m² and a highly interactive Science Center. Having something to look at lowers the pressure immediately.
Mirabellgarten for a free and clear frame
The Mirabellgarten is free to enter during the day all year and gives you a simple meeting place in the middle of the city. That is helpful if you do not want the meetup to become a spending situation.
Other formats that work
Jugendbüro or akzente as a real starting point
Sometimes the best first meetup is not "let's hang around somewhere", but getting orientation together. The Jugendbüro at Mirabellplatz 4 and akzente youth info in Schallmoos are good anchors for that.
FOTOHOF for a quieter frame
The FOTOHOF at Inge-Morath-Platz 2 is free and calm, which makes it a strong choice if images, exhibitions or a slower pace fit you better than coffee or cinema.
A short walk with a clear route
The point is not the walk itself but the clear route and the clear end. Salzach, Mirabell or a short loop through the city centre is better than "we'll just see".
When this does not fit
This does not fit well if you want a louder night program, an expensive meal or a totally open evening. For a first meetup, social quality matters more than supposed coolness.
Three rules for less awkward first meetings
Clear beats spectacular
One neutral place with a small activity is usually stronger than something that looks bigger on paper but creates too much pressure.
Short beats endless
First meetups in Salzburg often work better at 45 to 90 minutes than as an artificially long evening.
Repeatable beats perfect
If a second meetup feels easy afterwards, the format was probably good enough.
Conclusion
The best first meetups in Salzburg do not feel like event planning. They are reachable, not too expensive, not too loud and give you one shared anchor. Library, Haus der Natur, Mirabellgarten or an open youth format are usually stronger than anything that just sounds more exciting.