Expat and relocation groups online
Facebook groups built around specific neighborhoods or nationalities (search "[your nationality] in Istanbul" or your district name) tend to be more useful than generic "expats in Turkey" groups — the signal-to-noise ratio is much better when the group is narrow. Reddit's r/Turkey and r/Istanbul are good for specific questions, less good for ongoing friendships.
In-person meetups and language exchanges
Language exchange events (search "dil değişimi" or "language exchange Istanbul") are a reliable way to meet both locals who want to practice English and other foreigners in the same boat as you. Coworking spaces, even if you don't buy a membership, often run open community events worth showing up to in your first month.
Neighbors, your kapıcı, and your landlord
Don't underestimate this one — the people physically closest to you are often the fastest route to practical answers (which pharmacy, which plumber, which day is pazar day) that no forum post will answer as quickly. A basic greeting in Turkish and a willingness to ask goes a long way here.
Build your professional bench before you need it
A lawyer, an accountant (mali müşavir), and a doctor you can actually reach are each worth sourcing proactively rather than scrambling for one mid-crisis. Ask in neighborhood-specific expat groups for English-speaking recommendations with recent, specific experiences — not just a name someone heard once.
Coworking spaces double as a social starting point
If you're working remotely, a coworking membership solves two problems at once — a reliable place to work, and a built-in way to meet people on a similar schedule to yours.
Coworking & Internet Guide