For an Istanbul Bosphorus cruise around sunset, the evening dinner cruise is the option on TurB2C: three hours on a yacht, sailing between Europe and Asia while dinner is served.
It is an evening sailing rather than a short daytime sightseeing trip, so how much daylight you get depends on the season. Sunset in Istanbul comes late in summer and early in winter. The tour page shows the departure time for your date, so compare it with sunset on the day you plan to go.
The cruise lasts 3 hours on a mega yacht and is built around dinner: a 3-course Turkish meal served while you sail between Europe and Asia. Soft drinks are unlimited, and the list covers water, tea, coffee, juice and soda. Between courses there is a Turkish night show with belly dance, folk dance and a dervish performance, plus live music from a DJ and a saxophone player. Private tables and window seats are available, which matters if you want the water view during the meal.
The tour list names a 3-course dinner and unlimited soft drinks. It does not mention wine, alcohol, a separate snack service or a live guide giving commentary, so do not count on them. If any of these matter to you, check the tour page before booking. Think of this as a dinner and show evening on the water rather than a narrated sightseeing sail. The strait does the sightseeing itself: palaces, waterfront mansions and old fortresses line both shores.
Sunset time changes a lot through the year in Istanbul. In summer it comes late, so the light stays warm over the water for a long stretch. In winter it falls early, and most of a 3-hour evening cruise happens after dark. Spring and autumn usually give a mix of dusk and night lights. Check the departure time on the tour page for your date and set it against that day's sunset. It gets cooler on deck once the sun drops, so bring a light jacket.
Hotel pickup is listed as an option, so confirm on the tour page whether your hotel is covered and when you would be collected. Free cancellation is also listed, which is useful if the forecast changes your plans. Choose a private table if you are travelling as a couple or a small group and want some space. Window seats suit anyone who wants the skyline in view while eating. Come hungry, because dinner runs to three courses.