So many people show up! However, there not much food service and restrooms around view points. You might want to bring own food with you. All fireworks shot at the middle of Yokohama bay, so you can see many angle from anywhere around the bay.
23 rd Kanagawa News Paper Fireworks(神奈川新聞花火大会) has one of the great fireworks which has many Nishakudama (480m explosion size of Firework) fireworks. 250,000 people will join this firework festival, so the biggest yearly event in Yokohama. You will surprise with how huge sound those fireworks make. It is nice view with Yokohama Night view with great and huge fireworks.
8,000 fireworks
Access
0. at Yokohama Station.
1. use Minatomirai Line to Minatomirai (4 min.)
2. walk east (10 min.)
2 hr.
Let's learn MJER Iaijutsu. 
映画好き集まれ！