The Samsung Galaxy S8 will support dual SIM (but yours might not) - CNET
Samsung Galaxy S8+ International Version - Dual-SIM - 64 GB - Co [SM-G955F] - $257.59 : Unlocked Cell Phones, GSM, CDMA and More | ElectronicsForce.com
Samsung Galaxy S8 S8+ Plus 64GB DUAL SIM Unlocked Verizon AT&T T-Mobile Sprint A | eBay