You can automatically upload your activities to Strava from Zwift. Here's what you need to use Zwift:
- An indoor trainer, a speed/cadence sensor or power meter, and an ANT+ dongle.
- Go to Zwift's getting started page to find out exactly what you need by indicating your current gear setup in the prompts.
Set up the Automatic Syncing:
- Log in or create an account on Zwift.
- Click the arrow next to the Dashboard button at the top right.
- Go to Settings > Connections > Connect to Strava.
- Follow the prompts in the pop up to authorize Strava.
- You can disconnect your accounts from this Zwift page or you can revoke access from Zwift in your Strava Settings.
How to manually export and import:
From a computer, navigate to my.Zwift.com and click on MyActivities. Find your missing activity and click download. You will see a ZIP file. Navigate to https://www.strava.com/upload/select. Click 'Choose File' and select the ZIP file.
From a mobile device, navigate to my.Zwift.com in a mobile browser and log into your Zwift account. Click the 'Download' link under the activity you'd like to upload. A screen will appear to save the file - save the file to your preferred cloud-based service (requires cloud service storage such as iCloud, Dropbox, Google Drive). Open a new Chrome tab and navigate to https://www.strava.com/upload/select. Click the 'Choose File' link, choose the cloud service you saved the file to and upload the file.