"while sightseeing" is correct and can be used in written English.
It is typically used to indicate an action or activity that occurs at the same time as sightseeing. Example sentence: While sightseeing in Paris, we stumbled upon a quaint cafe and decided to stop for a quick bite.
I have often found myself ignoring the smartphone while sightseeing.
If you want to avoid looking out of place, consider wearing khakis and a polo shirt while sightseeing.
He is there, and Uncle vents his dislike of Italy and the Italians; he had been robbed while sightseeing in Nero's villa.
Wang Jian, above, the co-founder and co-chairman of the Chinese conglomerate HNA Group, fell to his death while sightseeing in France.
In an early scene, a Japanese tourist keels over while sightseeing; perhaps with the heat, more likely intoxicated by the visuals.
On a recent trip to Rome, Mr. Attanasio, 28, a court magistrate, stumbled on the new Dunkin' Donuts while sightseeing with his girlfriend.
A far more mature response than Senator Chuck Grassley's nit-twit tweets grumbling about the president urging progress on health care "while u sightseeing in Paris".
Sightseeing While Detroit's downtown is fairly compact, it is often advisable for visitors to rent a car to reach outlying attractions.
Sightseeing While gold Rolexes and diamond-encrusted Piaget wristwatches seem unlikely souvenirs from a city deeply associated with the austere principles of the reformer John Calvin, the reverse is true.
I'll be in London for about six days so I'll be hoping to do a bit of sightseeing while I'm down.
Now, Kevin will be heading out at 6 00 a.m. for a day of sightseeing while Geo will be hitting the hay from a night out on the town.
