If you hold the 
Best Western Rewards Premium Visa Signature, you're one step from Best Western Rewards Platinum: the card confers it automatically in the US, for as long as the account stays open and in good standing. No stays or spending thresholds are required — it's a straight benefit of holding the card.
From there, that Platinum status becomes your ticket into the cruise world. It matches once per lifetime to 
MSC Voyagers Club Silver, though that match lapses if you don't sail with MSC within three years of receiving it. MSC Silver in turn matches — again once per lifetime, and processed in about ten business days — into 
Explora Club (Explora Journeys) Silver, the end of this chain. The reference below maps both hops in full.
None of this costs anything beyond the card itself, but the middle leg is the one to watch: since the MSC match only lasts three years without a qualifying cruise, it's worth timing your Explora match before that window runs out rather than sitting on Best Western Platinum indefinitely.
multi-step⚠ one-time
how (3 steps)
Best Western Rewards Premium Visa Signature → Best Western Rewards Platinum (confer, official) 🇺🇸 — automatic as long as card account remains open and in good standing
Best Western Rewards Platinum → MSC Voyagers Club Silver (match, community-verified) 🌍 — once per lifetime; expires if no MSC cruise within 3 years
MSC Voyagers Club Silver → Explora Club (Explora Journeys) Silver (match, official) 🌍 — once per lifetime; proof of current tier required; processed in ~10 business days
Miles