Hey @Tuan42, 

Thanks for the post. If the activity was saved, you can submit a support ticket and our team can see if they can restore the activity for you. 

If the activity was discarded before it was uploaded ,we cannot retrieve the information. That's the final action when you're uploading from a mobile phone; you can save or discard the activity - discarding deletes the data

However, you do have a few good options for getting credit for your efforts. 

1. Manual Activity: 

You can create a manual activity to account for the lost mileage - although this won't count toward Strava Challenges and won't match to any segments. 

Please follow these steps to upload a manual activity:

Using our website:

1. Log into your Strava account at www.strava.com
2. Hover over the orange plus sign at the top right corner of the page
3. Click on "Add manual entry"
4. Select the activity "Sport Type" and fill out the fields listed
5. Click "Create" to complete your upload

Using the Android app:

1. Go to the Feed screen
2. Click the "+" button in the bottom-right

Using the iPhone app:

1. Go to the Feed screen
2. Click the "+" icon in the top-left

Directions can also be found in our help center article: Uploading Manual Activities

2. Activity sharing: If you were with a friend who recorded the activity with GPS

If you were riding or running with another Strava user, that friend can share their activity with you. You'll need to ask them to use the Add Friend button on their activity detail page which will allow them to share the activity with you. Once they've sent the invitation you can accept the copy of the activity as your own. If you accept the invitation, your friend's activity will appear on your Strava profile and feed as if it was your own. You will be grouped with the friend who invited you, the activity will count towards Challenges and Clubs you are a part of, and the activity will count towards your personal stats. The activity you're tagged in will not count towards segment leaderboards, running estimated best efforts and won't include heart, power, or cadence data.

For more information on how this feature works please see our Help Center article.

The question is, where did you delete it from?  If you just deleted it from your Strava account, then it is much easier than what Scout mentioned above.  If you did not delete it from the Garmin device itself, then it is still there and you just need to re-load the file to Strava.  Connect your Garmin device to your computer via USB cable.  Open your Strava account and select the "+" symbol in the top right and select "Upload Activity".  From there, select "File" on the left and click on "choose files".  From there, find your garmin device on the left and then find the activity files folder on the garmin.  Select the one for the date you deleted from Strava and upload from there.  

Děkuji za radu, moc mi pomohla a už jsem to i udělal 👍

Ještě jednou díky.

TRANSLATION: Thanks for the advice, it helped me a lot and I already did it 👍