As you can see from this post, I have lots and lots of Hakone suggestions.
Should you decide to stay the night over making this a day trip I highly recommend you stay at my favourite ‘just outside of Tokyo’ hotel – with our without kids (details here.)
Our favourite day trip in Hakone is to see Mt Fuji from Lake Ashi. Details here.
Here are my tips on Where to Stay in Hakone with kids?
And here I have Where to eat in Hakone with kids?
The number one kid-friendly option that always comes to mind for me in Hakone is the Hakone Open Air Museum. It’s fantastic for kids but also it’s so lovely for adults – even if you’re not really an arty person. It’s just a beautiful space and so relaxing just to have a lovely stroll and chat. All my Hakone Open Air Museum tips are here.
If you drive to Hakone, I recommend also checking out this lovely open playground for kids.