Three days is just about enough time to explore İstanbul’s main highlights, especially if you are staying close to them in Sultanahmet. Bear in mind that the heat and the crowds of high summer can be wearing and don’t try to cram in too much. And to save wasting time in queues, book your tickets online ahead of time.
This is what I would suggest:
DAY ONE
Spend most of the day in leisurely exploration of the Topkapı Palace including the Harem and Treasury. Afterwards you can pop into the Blue Mosque (Sultanahmet Cami) and take a turn around the historic Hippodrome or Gülhane Park.
DAY TWO
Explore the other historic sites of Sultanahmet – Hagia Sophia, the Yerebatan Cistern, the Archaeological Museum and the Great Palace Mosaic Museum (closed in 2024) which are all handily close together. You could also drop into the Ayasofya Hürrem Sultan Hamamı right in Sultanahmet Square to try out a Turkish bath originally designed for the wife of Sultan Süleyman the Magnificent. If it’s too expensive, amble along Divan Yolu to Çemberlitaş where another 16th-century Turkish bath designed by Sinan is cheaper (although not cheap).
DAY THREE
If the weather is good you can spend a happy day on a long Bosphorus boat ride that take you as far as Anadolu Kavağı whence you can climb the hill to Yoros Kalesi and gaze out over the Black Sea.
If the weather fails you can travel out to Edirnekapı to visit the Chora Church (closed Wednesdays) with its magnificent Byzantine mosaics and murals. Nearby you will be able to explore a stretch of the Theodosian City Walls and perhaps visit the new Panorama 1453 Museum to get a feel for what it was like on the day in 1453 when the walls were finally breached by the Ottoman troops led by Mehmed the Conqueror.
This should leave you enough time to travel across to Taksim Square (take the tram from Sultanahmet to Kabataş and then the funicular to Taksim) and walk along pedestrianised İstiklal Caddesi which is always heaving with people and which is lined with shops and restaurants offering something for all tastes and budgets. It’s a great introduction to modern Turkey and an antidote to all the tourism of Sultanahmet.
Shopping
With three days up your sleeve you will have greater flexibility when it comes to shopping. Some people will be itching to get into the Kapalı Çarşı (Grand Bazaar) despite its being a rather touristy experience.
More manageable are the Mısr Çarşısı (Egyptian or Spice Market) at Eminönu or the Arasta Bazaar beside the Blue Mosque. If you visit either of these you will still have at least half a day left for other sightseeing.
More interesting would be to take the tram and funicular to Tünel where you can explore the many small shops and trendy boutiques around the Galata Tower.
Eating
If time is tight and you don’t know the city well you might want to eat in Sultanahmet rather than venturing further afield and worrying about transport connections. Be aware, though, that prices are often higher and quality lower than in other parts of the city.
For something fairly authentic and not too expensive try Tarihi Sultanahmet Köftecisi Selim Usta on Divan Yolu which has been dishing up meatballs to enthusiastic locals since 1920.
Alternatively in summer you could take the suburban train from Sirkeci to nearby Kumkapı or Kocamustafapaşa (Samatya) to eat outdoors at one of the many fish restaurants.
