How to Purchase Tickets in Advance for Sights in Istanbul?

The Blue Mosque is going through major renovations with its exterior walls covered in scaffolding along with most of the interior, meaning that the blue interior tilework that made the Blue Mosque famous mostly can’t be seen now. The hilltop Suleiman Mosque built in the 1500’s makes a good substitute and has incredible views overlooking the Bosporus and Istanbul’s “New Town” in the distance. Don’t miss the nearby and ancient Hagia Sophia. Entry is free, so it’s best to get there first thing when the doors open, or book a skip-the
line tour for Topkapi Palace and Hagia Sophia with an agency like www.GetYourGuide.com or similar. Get Your Guide offers combination tours for Topkapi and the Hagia Sophia for about US$40 which means you can visit both sites in a single half-day. Both are attractions that rank among the most-visited in Istanbul and the lines can be overwhelming, especially when several cruise ships are in port.

There was a long- maybe 45-minute- line for the Galata Tower which might be less mid-morning to early afternoon.
The Basilica Cistern skip-the-line your with GetYourGuide now is US$21.
Dolmabahce Palace was built in the mid-19th Century and for four years was the Presidential Palace of Turkey’s first President, Kemel Ataturk. In retirement. this is also where Ataturk stayed as a guest and he died here in 1938.
This site is popular, but not as thronged as Topkapi or the Hagia Sophia. Booking a skip-the-line tour with GetYourGuide for US$35 or a similar tour agency can save time. Dolmabahce opens at 9am. It’s near the Besketis ferry terminal where you can board a ferry going toward the Black Sea along the Bosporus. In a couple hours roundtrip, you can see castle ruins and the Rumeli fortress ruins along with scores of Ottoman mansions and the historic Turkish Presidential Palace that’s off limits to travelers.
Have a great Trip!

When we visited Dolmabahçe Palace, arriving at 9:30 on a Sunday morning in May, 2022, the only long line was for security, which everyone must go through, regardless of tickets or tours. As long as the security line was, it moved quickly.

After that check, we walked to the ticket kiosk where there were 2 or 3 families ahead of us to buy tickets at 2 windows. (I suppose everyone else in the security line already had their tickets through a tour?) It took 5 minutes to buy our tickets.

I had called Dolmabahçe Palace (yes, long distance, the lady spoke cautious English) prior to our visit and confirmed it was not possible, through them directly, to buy tickets online. I did make a "reservation" but that had zero value on arrival. Perhaps if the ticket line had been longer we'd have been able to use a 3rd window that might have been for reservations.

ETA: ticket price 300 TL (foreigners) / $19 when I bought it, now $16.46, payable onsite with credit card.
The ticket price is good for both sides of the Palace, the Selamlik and the Harem, and includes a full audio guide.

At the time we went, there was a renovation project underway for the grounds, so there was little to see; perhaps that is finished.

ETA: no photos permitted inside.

I was never able to get the website to purchase Galata Tower tickets to work from the US.

We went twice in May, once on our own before our tour started, and again using our tour-supplied Museum Pass.

Saturday, Noon, on our own: there were 2 lines, one for tickets and one for entry. Each was about 15 minutes. My friend waited in one line while I waited in the other. Both were hot, no shade.

Monday, 8pm, using our tour-supplied MuseumPass: no need to wait in the ticket line, there was 1 couple ahead of us in the admission line; everyone else was already at the top of the tower, jockeying for position to get their best sunset selfies. Still, far less crowded than our Saturday mid-day visit. We had planned to be there at opening time, and then things happened. "Jams are fun!" :-)

Ticket price then was 130 TL; I see it is now 175 TL. The ticket price has risen faster than the exchange rate has fallen, so $9.60 now instead of $8.78 then. (Funny, when I researched in early May, the ticket price was only 100TL!)

Is the Blue Mosque worth visiting at this time?

Worth visiting to me: time + effort + cost compared to value

Admittedly, the value is lower than usual, though we were able to see the stained glass window, the cupola (a bit of scaffolding in the way, but mostly visible) and bits of blue tile work here and there.

But the time and effort were minimal, as we were in the area to visit the Hagia Sophia. And there is no entrance fee. The only thing you have to check is opening times, as it is closed during prayer.

I wouldn't have liked to pay a lot or stand in a long line. But quick and free: I'm glad I went inside. And if you've read my "3 Weeks in Turkey" trip report, you'll know there's a nearly unobstructed exterior view around the side near the Museum of Great Palace Mosaics.