Barcelona → to Istanbul

Only slightly. The seasonal median is around $180 round-trip and this fare is 16% under it. We do not call a drop notable until 20%, so this is an ordinary price for the route rather than a reason to hurry.

Across 11 months of cached-fare history, Dec comes out cheapest on this route. The best months to actually be in Istanbul are Apr–May · Sep–Oct — when those overlap, that's your window.

We do not publish a number for this, because we cannot measure it yet. Answering it honestly means watching the same departure date on this route over many weeks as it approaches, and that archive is still filling up — so any "book N days ahead" figure here would be borrowed from somewhere else rather than measured. What we can measure is which month is cheap: across 11 months of cached fares, Dec comes out lowest on this route. Our guide Why flight prices change covers what does move a fare.

Yes — the current board includes nonstop fares (Vueling). The outbound leg runs around 3.5 hours.

No — these are cached fares found on real searches (this one on 17 October). Airlines reprice constantly, so the booking search re-checks the live price before you pay. Fresher finds are far more likely to still be available.