Golden Keys can be obtained via Shift Codes.

You need a Shift Account to use the keys, so be sure to sign up for one. Shift Codes are used to collect Golden Keys which unlock a chest on Sanctuary that will reward you will loot! They are distributed sometimes at random by following Gearbox and the Borderlands social channels, or they can be distributed during various events. Once you've redeemed a key, they will show up in your mail in the game.

You can redeem keys via the following options:

53CJJ-FWS3W-WTXTS-TJBB3-CHFT3-Redeem for 5 Golden Keys.

CJ5JB-ZKSTK-KTF3S-3BJ3B-XCSRC-Redeem for 5 Golden Keys.

CTW3B-CFS3W-KBF3S-TBJB3-F6HF6-Redeem for 5 Golden Keys.

CBC3T-BX9T5-WBXTH-BTTBT-W9X6S-Redeem for 5 Golden Keys.

KBK33-9X9J5-53F3Z-JTJTJ-FFT5F-Redeem for 5 Golden Keys.

5TWBB-XFHBC-CBRTS-3JJ3B-KFCRC-Redeem for 5 Golden Keys.

5JKT3-6ZH3C-5J6B9-BJJ3T-SW9JF-Redeem for 5 Golden Keys (Expires Aug 16).

CJCJJ-HS9TW-5BFJS-JT3J3-BSF9Z-Redeem for 5 Golden Keys (Expires Aug 17).

53WTB-53BCC-CBRBZ-JJJ3T-KBBRK-Redeem for 5 Golden Keys.

WT5JJ-3BJW5-KJRTZ-J3BJJ-XBKXB-Redeem for 5 Golden Keys.

CBKBT-WWJKC-KJ6BH-B3JJJ-6T6RS - Expires Oct.

5J53T-BKJK5-CTXBZ-JJJTJ-WW6F3 - Expires Oct.

These codes are no longer available and can't be redeemed anymore.

9XWB3-BJ9RR-WTX5B-BTJ3B-WWRKX-Redeem for 5 Golden Keys (Permanent).

9XW3J-Z96R6-5BF5B-TJT3J-XR6CW-Redeem for 5 Golden Keys (Permanent).

S6W3B-X9XF6-5J6CJ-T3B3T-9ZJTH-Redeem for 5 Golden Keys (Permanent).

9FC33-5T9XX-K36KT-TTT33-TRJJJ-Redeem for 5 Golden Keys (Permanent).

Here's a look at a list of codes that have not expired yet: See Amazon Prime Day Gaming Deals Borderlands 1 Shift Codes (Working)

Borderlands 1 legendary weapons codes