Check Everywhere
Check between each Home screens. Flick back and forth between screens and ensure that the Safari icon isn’t on a different screen or hidden in a folder.
Reset Home Screen
If you cannot find the icon, you may want to reset the Home screen by going to “Settings” > “Reset” > “Reset Home Screen Layout“. This will reset all icons to their factory default positions on the Home screen.
Check Restrictions
This is the most common issue. A restriction setting can hide the Safari icon. Check under “Settings” > “General“ > “Restrictions“. Make sure “Safari” is set to “On” (green).
Last Resort
If none of the above works. It’s time to try a Restore with these steps:
Connect your device to your computer and launch iTunes.
Select your device on the left pane under “Devices“.
Select “Summary“.
Select “Restore“.
Hopefully after trying these steps your Safari icon will be restored to the Home screen of your iPhone, iPad or iPod Touch.
Credits to Mitch Bartlett