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I was wondering if someone who could help me. Myself and two friends are coming to Tokyo this April. We arrive at Haneda Airport at 7-8am and our check in time for our apartment is 2-3pm. Since we have quite a bit of time to kill I wanted to store our luggage at Tokyo Station and roam around the area before we go to our apartment.
I want to use the Gransta on the B1 floor at Tokyo station as it has a cloakroom for suitcases. (I think the coin lockers would be too small).

Looking at the Tokyo Station floor maps, I can see the best area is the Marunouchi central exit area, but I can't tell if I need a train ticket to access the Gransta.

We will be arriving via the JR Yamanote line. (Platform 4, I think).

So to access this Gransta cloakroom from the JR Yamanote line platforms, would I need to pass through a ticket barrier first? (As Tokyo station is so big and I have poor sense of direction, I just want to make sure I don't exit a barrier and then realise I have to go back through a barrier to get to Gransta.)

I will then be leaving Tokyo station via the Subway Marunouchi Line. So when I return to the Gransta to collect our suitcases after I've finished sightseeing/shopping in the area, would I need to return through a ticket barrier again? And does this ticket barrier only give access to the JR lines? Or would I still be able to access the Marunouchi Line?

I'm open to suggestions as well. (I.e. Would a Suica Pass be most convenient to tap in and out, although I guess I wouldn't want to keep paying to get in an out of Gransta.)

Basically I'm trying to avoid having to by several train tickets just to drop off and pick up luggage.

Many thanks in advance!

Ahh I've figured it out by myself now. So all okay! Shame no one knew the answer at the time.

ninjalin8887787 san,
konnichiwa.
That’s good.
Have a good trip in Japan.

Yuki　由紀
Team JapanesePod101.com

Yes, there is a luggage storage area by the Marunouchi North exit (next to the travel centre). They take over-size items and the fee is per bag (Y500).

どうもありがとう、由紀様。 もちろん！日本で旅行はいつも素晴らしいです。

Thanks, Patrick. That's the one I found that solved my problem. The JR East Travel Service Centre has a section that stores luggage. It is good since it means I can explore the areas not confined by the ticket barriers.

Also, since I won't be jumping back on any JR rail lines, Storing at the Gransta would mean I'd have a problem getting back out of the barriers after collecting the suitcases.

patrick_harnett　さん、
Konnichiwa.Thank you for the useful information.

ninjalin8887787　さん、
Please tell us your experience after the trip.
Yuki 由紀
Team JapanesePod101.com

Oh I just wanted to mention, the storage of the suitcase at the JR East Travel Service Centre was very simple. Definitely recommended if you want to wonder around the moat of the Imperial Palace and the lovely park with water fountains without having to carry your luggage.

When collecting our luggage we just caught a taxi just outside of Tokyo Station on the Marunouchi side. Not even a minute walk from the baggage service to the taxi stand. Very convenient, especially as we were exhausted from our flight that day.

Thanks for all the help!