The triple disaster of March 11, 2011 posed a formidable challenge for Japanese society in general, and for affected coastal communities in particular. In the immediate aftermath of the catastrophe, there was widespread support for the construction of high seawalls to protect communities. However, many communities began questioning this approach. In Maehama, the question of land reconstruction and protection gave rise to a set of complex responses. The government aimed to put in place even higher seawalls; however, the local community proposed instead to mark the boundary of high water with trees and stakes. These solutions instantiate different ways of infrastructuring the post-tsunami environment for safety; they carry different assumptions about infrastructure itself. Whereas the seawall solution was technical and quantitative, centering on the question of height, the boundary markers embedded qualitatively different assumptions about what makes a workable infrastructure. In particular, this difference centered on issue of visibility. On the one hand, the seawall was meant to slowly become unremarkable, whereas the boundary markers were specifically intended to maintain community memory. On the other hand, the seawall would make the sea itself invisible, whereas keeping the sea in sight is very important to villagers. However, the opposition between these forms of infrastructuring the environment was not total. A solution was gradually negotiated in which the sea wall and the boundary markers could complement each another. This situation highlights the intricate, transformable relation between visible and invisible forms of infrastructure.