From Asakusa, an alternative to walking for reaching Tokyo Bay is to take the Tokyo Cruise Ship water bus. It follows the Sumida River southwards until Hamarikyu Garden and Hinode Pier. It is then possible to switch boat to pass under the Rainbow Bridge and reach Odaiba.
This is where the Sumida River borders both Arakawa City (on the south side) and Adachi City (north). It is a bit out of the way but it is a nice and quiet walk.
A nice thing to do after visiting Asakusa and Tokyo Skytree is to walk south along the Sumida River. It is possible to go all the way to Tokyo Bay on foot (for example, ending at Harumi Passenger Ship Terminal). In this post, I stopped at Tsukiji, after making a detour by Tsukishima Island, where the Sumida River forks into 2 channels before reaching Tokyo Bay.
The Sumida River (隅田川; Sumida-gawa) is a river in eastern Tokyo that starts at the Iwabuchi Sluice Gate in Kita and flows into Tokyo Bay. There is a walkway along its bank almost everywhere along the way. Here are photos of the walk starting from Asakusa and going north to Minami-Senju, in Arakawa City.
Above, Sumida River from the Tokyo Skytree observatory.
In May, starting at Kameido station, I walked east towards Edogawa City, until I reached the Arakawa River. I then crossed it in order to visit Funabori Tower Hall and its observatory. I went back to the other side of the Arakawa and walked along the Kyu-Nakagawa River (旧中川) then turned west at the Kitajukken River (北十間川), which goes all the way to the Sumida River, passing in front of the Tokyo Skytree. I ended the day with the Sanja Matsuri in Asakusa.
The Old Iwabuchi Sluice Gate (aka Red Sluice Gate or Akasuimon) is a flood gate located in Akabane (Kita City), at the spot where the natural Arakawa River becomes the Sumida River. The construction of the gate in the 1920’s was accompanied by the digging of an artificial canal, starting at the same location: This canal is the Arakawa River that flows through Tokyo. The system was designed so that, in case of a flood, the gate would be closed and overflow water would instead get into the canal and quickly dumped into the sea. The Red Gate still stands but its role has been taken over by the new Iwabuchi Sluice Gate (in blue). This page has more context about the floods of the Sumida River and the gates.
The gates are in the middle of a large park that I visited a few weeks ago.
Sumida Park straddles both sides of the Sumida River near Senso-ji Temple in Asakusa. It contains a large number of cherry trees that make it a very popular spot during cherry blossom season. I went there after Ueno Park, since it is quite close.
After visiting Senso-ji, I went for a walk in the area of Tokyo east of the Sumida River.