I’m coming to İstanbul for the first time; does it make sense to visit Ayasofya, Sultanahmet Camii and Topkapı Sarayı on the same day, and what should be the best order?
Yes, visiting these three on the same day makes sense, because they are all in Sultanahmet and within walking distance of one another. I recommend starting the route early in the morning with Topkapı Sarayı: the courtyards and the Harem section will be calmer, and you can spend time at the palace’s scenic viewpoints without rushing.
After that, moving on to Ayasofya creates a good flow. Since Ayasofya offers an intense experience both architecturally and historically, don’t approach it as a stop where you can “quickly look around and leave.” Sultanahmet Camii is very close by; because visiting arrangements can change due to prayer times, the healthiest option is to follow the directions at the entrance.
For a lunch break, the area around Sultanahmet Köftecisi, Arasta Çarşısı or the cafés on the Gülhane side offer practical options. If you still have energy, be sure to add the Dikilitaşları and Alman Çeşmesi in Hipodrom Meydanı as well; without spending extra distance, you will better understand İstanbul’s Byzantine and Ottoman layers.
Since ticketed sites and visiting hours can change seasonally, it is a good idea to check official sources before you go. In summer, midday hours can be crowded and hot; comfortable shoes, clothing that covers the shoulders, and an offline map on your phone will make things easier. For a calmer experience, weekdays and early morning hours are the best choice.