I first inquired from their website and enjoyed a swift reply to my request for a short notice all-day tour (just a couple days in advance). In my case, they didn't ask for any online payment, just saying I should bring the cash with me. On tour morning, my bus driver arrived about 3 minutes before the 8 o'clock agreed-to time, and off we went to a staging area where people in different tours got into their specific buses. The guide was easy to understand, very kind and knowledgeable about the great history of Turkey from the early Greeks and Romans to the Ottoman and Byzantine periods up through the 20th century. He kept us moving to stay on time as we went to various mosques, museums, palaces and the lunch date (which, by the way was in the Olive restaurant's rooftop room and was a nice lunch). After we finished up, several of us decide to go visit the Basilica Cistern as recommended by our guide.
If you own or manage Turkland Tours Istanbul Day Tours, register now for free tools to enhance your listing, attract new reviews, and respond to reviewers.