: As the official on-field outfitter for MLB, the official Nike website carries the current season's on-field and City Connect designs.

: The official online store of Major League Baseball offers the widest selection of jerseys for all 30 teams. They provide various tiers, including Authentic (on-field specs), Limited (premium fan version), and Replica (standard fan version).

For authentic on-field jerseys or officially licensed fan replicas, these platforms are the most reliable sources.

: As the operator for many official league stores, Fanatics carries an identical inventory to MLB Shop, often featuring exclusive "Jersey Assurance" programs that protect fans if a player is traded.