By the Waterfront Et Cetera (For Adults) (水辺にまつわるエトセトラ（成人済）, Mizube ni Matsuwaru Etosetora (Seijin-zumi)) is the 6th episode of Blend S. The episode premiered on November 11, 2017.
Maika, Dino, and Mafuyu are at the riverbank for a barbecue, while Kaho, Miu, and Kouyou were forced to come along since they would rather stay indoors. Maika brought an oddly realistic tuna, so Dino sliced and grilled it so that everyone can enjoy eating it. As the sun sets and the cafe staff return home, Dino notices that Maika wanted to go to the beach one day. The next day, Maika and Dino went shopping in order to buy a swimsuit for her. The following day, the cafe staff are all at the beach. Meanwhile Kouyou was concerned about the way Kaho was wearing. Later, while going to buy the shaved ice, Maika cuts herself on her foot, so Dino had to treat her foot with a bandage. As the sun sets, Dino asked Maika if she had a good time, in which she responded yes.
By order of appearances: