Harem★Island ~Otoko<Onna 7nin Natsu Monogatari Theme Park wa Oosawagi~

Masayuki Shimada works part time at a major theme park that’s situated on a deserted island. While working there he does several odd jobs that have him meeting his fellow workers on the island. Of his co-workers there happens to be six lovely women. Being a fantasy-themed park, they all cosplay as various characters to further add fuel to his lusting. In a tactful (but probably unintentional) manner, he begins courting all the women and begins his own personal harem at the park.

[From White Masq]