At Baselworld 2019, the big news from Rolex was that, the brand new 18k white gold Yacht-Master 42 ref. 226659 with a bigger 42mm case size was released, which is the first time the Yacht-Master collection over the 40mm size mark. However, there are also several sub-40 mm Yacht-Master models made by Rolex. Today let’s conclude how many Rolex Yacht-Master sizes are total there are.
At present, Rolex has three sizes of the Yacht-Master, including the new Yacht-Master 42 we mentioned above, the Yacht-Master 40, and the Yacht-Master 37. While the largest model is exclusively offered in white gold, the other two sizes are made in Everose, two-tone Everose, and stainless steel, and two-tone platinum and stainless steel separately. 
What should mention is that the Yacht-Master is the only Rolex collection that offers a functional bezel on a case that’s smaller than 40mm. For someone who has smaller wrists hunting for Rolex sports, replica watches the Yacht-Master 37 (a size first introduced in 2015) is a wonderful choice.
In early 1992, Rolex first announced the Yacht-Master collection with the yellow gold Yacht-Master ref. 16628, which sported a 40mm case size. Two years later in 1994, two more sizes were unveiled by Rolex: the mid-size Yacht-Master ref. 68628 with a 35mm case and the ladies Yacht-Master ref. 69628 with a 29mm case. Rolex offered these three different sizes within the Yacht-Master collection from then on until 2015.
In 1999, Rolex released the Rolesium edition of the Yacht-Master. For those who may not know, “Rolesium” is Rolex-speak for marrying platinum and steel on one watch, which is a combination still available in the Yacht-Master collection currently.
Eventually, the Rolesor (Rolex’s term for gold and steel watches) versions of the Yacht-Master introduced two models in yellow gold and stainless steel in 2005. This particular metal configuration is not produced by Rolex any longer, the Everose gold and stainless steel Rolesor watches have been the replacement. Rolex finally dropped the 29mm and the 35mm sizes of the Yacht-Master and kept the 40mm size as well.
In brief, there are five available different sizes of the replica Rolex Yacht-Master collection if the discontinued sizes are included: 42mm, 40mm, 37mm, 35mm, and 29mm. Additionally, if we include the Yacht-Master II model (fairly speaking, which is a completely different watch despite the shared name) with its massive 44mm case, that’s six sizes totally. No other Rolex Professional collection can offer such an assortment of sizes as Yacht-Master.