How to import contacts from galaxy s3 to nexus 5? How do you import contacts from a Galaxy S3 to a Nexus 5?
They're both Android devices, so is it a simple process?
Do I need to save them to a SIM card?
Several ways actually. The most simple way I found was to sync all your addresses to a Google Account. If you don't have one create one. On the S3:  


From Settings Scroll down and choose Accounts and Sync.  
Choose Add Account.  
Choose Google.  
Choose Existing to add an existing account.  
Type in the email id of the account.  
Fill in password and sign in.`  


On the other device, simply sync to the account again. All your contacts will be pulled in.