You can watch the anime series "Horimiya" streaming on several platforms:

• Hulu
• Crunchyroll (including Crunchyroll Amazon Channel) where you can watch for free with ads
• You can also purchase and download episodes on Apple TV, Amazon Video, and Fandango At Home

Crunchyroll offers both subtitled and English dubbed versions of Horimiya, accessible through their website or app

. Hulu requires a subscription but offers a free trial period, which might be useful if you want to watch the series without immediate payment

. In summary, the most straightforward legal options are Hulu and Crunchyroll, with Crunchyroll providing a free ad-supported viewing option.