Topological Weyl semimetals typically feature twofold degenerate points of bulk bands, which can be classified by four distinct topological charges, i.e., charge 1, 2, 3, or 4 in the two-band Hamiltonian with crystal symmetries. However, while charge-1, charge-2, and even charge-4 Weyl points have been observed in various systems, the experimental observation of the charge-3 Weyl point (despite theoretical predictions) remains scarce. Here, we report the experimental observation of a pair of charge-3 Weyl points in a three-dimensional acoustic crystal with $C_{6z,3}$ screw symmetry, which exhibits unique hourglass-type band structures. The existence of three branches of surface arcs linked to each charge-3 Weyl point is confirmed by experimental observations, consistent with tight-binding models and numerical calculations. By projecting paired charge-3 Weyl points onto the top surface, the sixfold helical surface arcs are further observed. Our findings locate the missing experimental piece of the family of topological acoustic Weyl semimetals.

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• Acoustic metamaterials
• Topological materials
• Weyl semimetal
• Acoustic techniques
• Band structure methods
• Finite-element method
• Tight-binding model