By default, all Vimeo videos will play inline on mobile browsers. Instead of entering fullscreen mode within the native device player, your video will play directly in the webpage where it’s embedded. Viewers can enter still fullscreen mode by clicking the fullscreen button in the player.
Inline playback allows for an uninterrupted browsing experience for your viewers, provides a more unified viewing experience across devices, and offers support for more embedded player customizations on mobile. These customization options include custom video controls, quality/speed selections during playback, custom logos, and a more seamless experience for email capture and end screens.
If you prefer for your videos to play in fullscreen on mobile, you can add the ?playsinline=0 parameter to the end of the player URL in your embed code. This will force your video to load in fullscreen mode once the viewer clicks on play.
Example embed code:
<iframe src="https://player.vimeo.com/video/137805268?playsinline=0" width="640" height="360" frameborder="0" webkitallowfullscreen mozallowfullscreen allowfullscreen></iframe>