“Can I convert to Shinto?” This is a question I occasionally see online, or the variant “How can I convert to Shinto?”. They both seem like reasonable questions: to convert to Christianity you should be baptised and there are said to be some religious communities that do not accept converts — you have to be born a member. However, neither question really applies to Shinto.
Shinto is not an identity, it is a group of related activities. This may be why there is no word in English for someone who follows Shinto; there is no common word for it in Japanese, either. Some very approximate statistics from the UK and Japan also illustrate the difference well. About 60% of people in the UK identify as Christian, and about 3% actually go to church. On the other hand, about 3% of people in Japan identify as Shinto, and about 60% go to jinja.
About 10 years ago, Jinja Shinpōsha published a book, Shintō no Iroha, as a general introduction to Shinto. It is in a question-and-answer format, and one of the questions is “How do I convert from Buddhism to Shinto?” The answer starts by saying that Shinto doesn’t really do conversions. There are no ceremonies for it, and because it’s made up of traditional ceremonies and customs, there is nothing like Christianity or Buddhism where you are attached to a particular variety of Shinto.
In short, you cannot convert to Shinto, because Shinto is not something you are.
On the other hand, anyone can participate in Shinto rituals. If a foreign tourist goes to a large jinja in a tourist centre (such as Tokyo or Kyoto) and asks for a ceremony, the miko will probably briefly panic, before bringing the person who has the most confidence in their English to sort out what the tourist wants. (If the tourist does not speak English, further panic will ensue.) If the same tourist goes to a small jinja, or one outside tourist areas, the panic may last a bit longer, but the only problem is the communication problem. If a foreign tourist wants to receive an ofuda so that she can pay her respects to the kami in her own home, or an omamori for some specific benefit, then that is also no problem.
It is true that there are some ceremonies you can only participate in if you are descended from the correct family, but there is a different family for each ceremony. I could never be the chief priest of Izumo Taisha, in Shimane prefecture, because that priest must be the descendant of a line that goes back 1,500 years. However, members of that family could never be the chief priest of Aso Jinja, in Kumamoto prefecture, because the family line there goes back to the same period. On the other hand, there is nothing other than distance preventing me from participating in many of the ceremonies at those jinja.
Shinto is something you do, and one of the fundamental principles of the tradition is that anyone can do those things.
October 2020 Addendum: Since writing this post, I have written Shinto Practice for Non-Japanese, a short book on exactly how you can participate in Shinto rituals. If you are interested in more details, that is a good place to start. (Affiliate link. Plus I get royalties on the book because I wrote it.)