Hakone-Yumoto Station to Fuji-Q highland

Hi
I plan to travel from Hakone-Yumoto to Fuji-Q Highland by taxi.
Do I need to book a taxi in advance ? If needed, where can I book a taxi? Do I book it at the tourist centre? Is it possible to hire a taxi on the day itself instead of booking in advance?
What is the estimated cost of the taxi ride for 4 passengers?
Thank you

Taxi would be very expensive as they are not close.

If u take fr HakoneYumoto stn, there is a taxi stand, no reservation is required.
If u want to take fr the front of a hotel/ryokan, make a reservation ASAP.

The fare is around 17,500Y, 57.1km, around 1h40mins, no toll.
https://www.taxifarefinder.com/main.php?city=Tokyo-Japan
However, regular size car driver cannot allowed if u are super fat(body wide) or if too big luggages.
https://47fkin.com/wp-content/uploads/2019/04/01a38463999048078b5bf4d6...
https://www.youtube.com/watch?v=ynNdAHuTS18
https://www.youtube.com/watch?v=Upcw7Zx8mvs

If u book a larger size taxi, it will cost over 20,000Y exactly, but it will be under 1.5 times.
If u come back to HakoneYumoto again, rental car is obviously cheaper,
but if someone does not have a Japanese driver's license
or "IDP" that can be driven in Japan, u cannot rent a car, anyway.
https://rent.toyota.co.jp/eng/drive/

And, Idk if ur country has Uber or Uber-like services, but u can't do the same in Japan.

To go FujiQ by local bus, u have to make a detour (two transfers) and time longer abt 2.5 - 3hrs,
not so many operating numbers, it is the cheapest if oneway, though.

Thank you for the useful information:) We'll re-consider our itinerary.