diff --git a/score.go b/score.go
index d2e54528..048cba20 100644
--- a/score.go
+++ b/score.go
@@ -976,12 +976,14 @@ func (ps *peerScore) getIPs(p peer.ID) []string {
 			ip4 := ip.String()
 			res = append(res, ip4)
 		} else {
-			// IPv6 address -- we add both the actual address and the /64 subnet
+			// IPv6 address -- we add both the actual address and (optionally) the /64 subnet
 			ip6 := ip.String()
 			res = append(res, ip6)
 
-			ip6mask := ip.Mask(net.CIDRMask(64, 128)).String()
-			res = append(res, ip6mask)
+			if ps.params.IPv6SubnetColocation {
+				ip6mask := ip.Mask(net.CIDRMask(64, 128)).String()
+				res = append(res, ip6mask)
+			}
 		}
 	}
 
diff --git a/score_params.go b/score_params.go
index 3a205840..099165d6 100644
--- a/score_params.go
+++ b/score_params.go
@@ -73,6 +73,9 @@ type PeerScoreParams struct {
 	IPColocationFactorThreshold int
 	IPColocationFactorWhitelist map[string]struct{}
 
+	// IPv6SubnetColocation controls whether /64 IPv6 subnets should be considered colocated.
+	IPv6SubnetColocation bool
+
 	// P7: behavioural pattern penalties.
 	// This parameter has an associated counter which tracks misbehaviour as detected by the
 	// router. The router currently applies penalties for the following behaviors: