The present technology relates to a solid-state imaging element configured so that pixels can be more reliably separated, a method for manufacturing the solid-state imaging element, and an electronic apparatus. The solid-state imaging element includes a photoelectric converter, a first separator, and a second separator. The photoelectric converter is configured to perform photoelectric conversion of incident light. The first separator configured to separate the photoelectric converter is formed in a first trench formed from a first surface side. The second separator configured to separate the photoelectric converter is formed in a second trench formed from a second surface side facing a first surface. The present technology is applicable to an individual imaging element mounted on, e.g., a camera and configured to acquire an image of an object.