Can you use a Suica card in Hakone?
What the card does
Tap in and out on ordinary trains, including the Odakyu run out from Shinjuku, and use it on many buses. It saves you working out fares at a machine, and it works the same way in Hakone as it does in Tokyo. For the two ropeway-and-boat legs, it does nothing.
What the card does not do
It does not cover the ropeway or the cruise, and it is not the Hakone Freepass. The pass is issued separately, covers eight transport systems including the ropeway and the cruise, and its shortest version is two days at ¥7,100 ex-Shinjuku. Whether that is worth buying for one day is a real question with a close answer, worked through on the Freepass page.
One more thing about the Romancecar: the limited-express surcharge of ¥1,200 each way is a reserved seat, and it is charged separately from your base fare whether you are paying by IC card or holding a pass.
One IC card cannot be shared by two people through a gate. If you are travelling as a pair, you need one each, which catches out couples who have been sharing a phone wallet all trip.
So what should you carry?
If you are riding the full loop, the pass and an IC card do different jobs and neither replaces the other. If you are only going up and back for the ropeway, an IC card gets you to the mountain and you buy the ropeway separately — the fares, the four stations and the seasonal hours are on the ropeway page.
Frequently asked questions
Does Suica work on the Hakone Ropeway?
No. IC cards do not cover the Hakone Ropeway or the Lake Ashi sightseeing cruise. The ropeway is ¥2,000 one way for an adult and ¥3,000 return, or it is included in the Hakone Freepass. IC cards do work on ordinary Odakyu and JR trains and on many buses.
Can I use Suica instead of the Hakone Freepass?
Only if your day does not include the ropeway or the cruise, since an IC card covers neither. The Freepass is a separate product covering eight transport systems, sold as a minimum of two days at ¥7,100 ex-Shinjuku. There is no one-day version.
Do I need a Suica card to get from Tokyo to Hakone?
No. You can buy a ticket at the machine, and the Romancecar seat is reserved separately anyway — base fare ¥1,270 plus a ¥1,200 limited-express surcharge, ¥2,470 in total from Shinjuku. An IC card is simply more convenient. The route comparison is on Tokyo to Hakone.