1girl, ahoge, back_cutout, blue_sky, blush, casual_one-piece_swimsuit, choker, clenched_hands, clothing_cutout, cloud, day, eyelashes, flat_chest, flower, hair_between_eyes, hair_flower, hair_ornament, hand_up, looking_at_viewer, low_twintails, medium_hair, one-piece_swimsuit, onii-chan_wa_oshimai!, open_mouth, oyama_mahiro, partially_submerged, pink_choker, pink_hair, sky, solo, swimsuit, twintails, untied_swimsuit, water, wavy_mouth, yellow_eyes, yellow_one-piece_swimsuit, yuruligon