During my last trip to Tokyo, I made my pilgrimage back to Odaiba to pick up some limited edition Coke bottles. The World of Coca-Cola has since closed and moved to a smaller location inside AQUA CiTY mall on the 3rd floor. Across from the mall was the 12th Hilton property in Japan which opened in 2015. Before taking the Yurikamome back to Shinjuku, I stopped by the Hilton Tokyo Odaiba and asked for an envelope.
Since I had to transfer in Shimbashi for JR back to Shinjuku, I picked up the Shimbashi eki stamp for the Hilton envelope and affixed a crested ibis and Japanese primrose which I picked up the day before. It didn't take long before I found a pair of large red mailbox outside the station for me to send my third Hilton cover back home.
P.S. My previous Hilton cover had Shinjuku postmarks that complemented the Shinjuku eki stamp. However, the cover I mailed outside Shimbashi eki ended up with a Ginza postmark. I checked Google Map and the nearby Ginza post office appears to be a larger post office than the Shinbashi post office.