Exit Eminönü metro, cross Galata Bridge toward the Golden Horn side, then head left toward the Spice Bazaar area. You'll smell them before you see them — Vendors grilling fresh fish right on moored boats, whatever they hauled in that morning. Mackerel, sea bass, sometimes bluefish when it's running.

The sandwich runs about 70 lira: grilled fish, onions, lettuce, tomato, lemon squeeze, all stuffed into crusty bread that'll soak up the juices. Messy as hell but it's the best cheap meal in the tourist zone. Fish is legitimately fresh here — They're not reheating yesterday's catch like most restaurant scams.

Technique matters, so watch your vendor. Look for proper char marks, fish that flakes when they flip it, smoke billowing from actual charcoal. Avoid boats where guys are just heating pre-cooked fish on cold grills. The good vendors work until 9pm, later if crowds are heavy.

Pro kitchen tip: grab extra napkins from nearby shops first. You'll need them. And eat it standing there — This sandwich doesn't travel well, turns into soggy bread mush after 10 minutes. But when it's fresh off the grill with that char flavor and sea salt? Nothing beats it for street food authenticity in tourist central.