Abstract: A subsea well uses a shuttle valve for connecting tubing annulus passageways between a riser and a tree of a subsea well. The riser has a connector that lands on an upper end of a tree. The riser connector has a production passage and an annulus port. An internal tree cap is located within the tree. A production passage passes through the internal tree cap and an annulus passage communicates with a top surface of the internal tree cap and the annulus passage of the tree. The shuttle valve is located within a valve receptacle or valve cylinder in an upper end of the annulus passage. A portion of the shuttle valve extends above the upper surface of the internal tree cap so that the shuttle valve opens when the riser connector lands on the top of the internal tree cap. Alternatively, the shuttle valve may be hydraulically actuated.