"Yottoko Nondonko"
A short walk from the Yaesu South Exit of Tokyo Station, you'll find Tokyo Midtown Yaesu.
On the 2nd floor, there's a public space called Yaesu Public, where you can relax, meet up with friends, have a drink, or grab a bite to eat. It has a lively atmosphere!
Bringing in food and drinks is prohibited between 11:00-14:00 and after 17:00, but otherwise, it seems like you can enjoy your own lunch here.
There's an area called Ichijiteishi where you can take a break, but it was too crowded, so I'll have to visit again. There were also places to sit and rest near the entrance.
If you're looking for a more peaceful place to relax, this terrace is recommended.
So, why not give these rest areas around Tokyo Station a try?
