diff --git a/crates/caldav/src/lib.rs b/crates/caldav/src/lib.rs
index 0a15a17..b1a8f4a 100644
--- a/crates/caldav/src/lib.rs
+++ b/crates/caldav/src/lib.rs
@@ -22,8 +22,11 @@ pub use error::Error;
 pub struct CalDavPrincipalUri(&'static str);
 
 impl PrincipalUri for CalDavPrincipalUri {
+    fn principal_collection(&self) -> String {
+        format!("{}/principal/", self.0)
+    }
     fn principal_uri(&self, principal: &str) -> String {
-        format!("{}/principal/{}/", self.0, principal)
+        format!("{}{}/", self.principal_collection(), principal)
     }
 }
 
diff --git a/crates/caldav/src/principal/mod.rs b/crates/caldav/src/principal/mod.rs
index 69bf843..5077a4d 100644
--- a/crates/caldav/src/principal/mod.rs
+++ b/crates/caldav/src/principal/mod.rs
@@ -74,6 +74,11 @@ impl Resource for PrincipalResource {
                         ))
                     }
                     PrincipalPropName::AlternateUriSet => PrincipalProp::AlternateUriSet,
+                    PrincipalPropName::PrincipalCollectionSet => {
+                        PrincipalProp::PrincipalCollectionSet(PrincipalCollectionSet(
+                            puri.principal_collection().into(),
+                        ))
+                    }
                 })
             }
             PrincipalPropWrapperName::Common(prop) => PrincipalPropWrapper::Common(
diff --git a/crates/caldav/src/principal/prop.rs b/crates/caldav/src/principal/prop.rs
index fa3043a..f62eb29 100644
--- a/crates/caldav/src/principal/prop.rs
+++ b/crates/caldav/src/principal/prop.rs
@@ -18,6 +18,8 @@ pub enum PrincipalProp {
     GroupMembership(GroupMembership),
     #[xml(ns = "rustical_dav::namespace::NS_DAV", rename = b"alternate-URI-set")]
     AlternateUriSet,
+    #[xml(ns = "rustical_dav::namespace::NS_DAV")]
+    PrincipalCollectionSet(PrincipalCollectionSet),
 
     // CalDAV (RFC 4791)
     #[xml(ns = "rustical_dav::namespace::NS_CALDAV")]
@@ -36,3 +38,6 @@ pub struct CalendarHomeSet(#[xml(ty = "untagged", flatten)] pub(super) Vec<HrefE
 
 #[derive(XmlDeserialize, XmlSerialize, PartialEq, Clone)]
 pub struct GroupMembership(#[xml(ty = "untagged", flatten)] pub(super) Vec<HrefElement>);
+
+#[derive(XmlDeserialize, XmlSerialize, PartialEq, Clone)]
+pub struct PrincipalCollectionSet(#[xml(ty = "untagged")] pub(super) HrefElement);
diff --git a/crates/carddav/src/lib.rs b/crates/carddav/src/lib.rs
index 43d75b7..5cfbc5f 100644
--- a/crates/carddav/src/lib.rs
+++ b/crates/carddav/src/lib.rs
@@ -22,8 +22,11 @@ pub mod principal;
 pub struct CardDavPrincipalUri(&'static str);
 
 impl PrincipalUri for CardDavPrincipalUri {
+    fn principal_collection(&self) -> String {
+        format!("{}/principal/", self.0)
+    }
     fn principal_uri(&self, principal: &str) -> String {
-        format!("{}/principal/{}/", self.0, principal)
+        format!("{}{}/", self.principal_collection(), principal)
     }
 }
 
diff --git a/crates/carddav/src/principal/mod.rs b/crates/carddav/src/principal/mod.rs
index c12f319..bae54e3 100644
--- a/crates/carddav/src/principal/mod.rs
+++ b/crates/carddav/src/principal/mod.rs
@@ -70,6 +70,11 @@ impl Resource for PrincipalResource {
                         ))
                     }
                     PrincipalPropName::AlternateUriSet => PrincipalProp::AlternateUriSet,
+                    PrincipalPropName::PrincipalCollectionSet => {
+                        PrincipalProp::PrincipalCollectionSet(PrincipalCollectionSet(
+                            puri.principal_collection().into(),
+                        ))
+                    }
                 })
             }
 
diff --git a/crates/carddav/src/principal/prop.rs b/crates/carddav/src/principal/prop.rs
index 3a6d968..6929a26 100644
--- a/crates/carddav/src/principal/prop.rs
+++ b/crates/carddav/src/principal/prop.rs
@@ -1,9 +1,6 @@
 use rustical_dav::{extensions::CommonPropertiesProp, xml::HrefElement};
 use rustical_xml::{EnumVariants, PropName, XmlDeserialize, XmlSerialize};
 
-#[derive(XmlDeserialize, XmlSerialize, PartialEq, Clone)]
-pub struct AddressbookHomeSet(#[xml(ty = "untagged", flatten)] pub(super) Vec<HrefElement>);
-
 #[derive(XmlDeserialize, XmlSerialize, PartialEq, Clone, EnumVariants, PropName)]
 #[xml(unit_variants_ident = "PrincipalPropName")]
 pub enum PrincipalProp {
@@ -15,6 +12,8 @@ pub enum PrincipalProp {
     GroupMembership(GroupMembership),
     #[xml(ns = "rustical_dav::namespace::NS_DAV", rename = b"alternate-URI-set")]
     AlternateUriSet,
+    #[xml(ns = "rustical_dav::namespace::NS_DAV")]
+    PrincipalCollectionSet(PrincipalCollectionSet),
 
     // CardDAV (RFC 6352)
     #[xml(ns = "rustical_dav::namespace::NS_CARDDAV")]
@@ -30,5 +29,11 @@ pub enum PrincipalPropWrapper {
     Common(CommonPropertiesProp),
 }
 
+#[derive(XmlDeserialize, XmlSerialize, PartialEq, Clone)]
+pub struct AddressbookHomeSet(#[xml(ty = "untagged", flatten)] pub(super) Vec<HrefElement>);
+
 #[derive(XmlDeserialize, XmlSerialize, PartialEq, Clone)]
 pub struct GroupMembership(#[xml(ty = "untagged", flatten)] pub(super) Vec<HrefElement>);
+
+#[derive(XmlDeserialize, XmlSerialize, PartialEq, Clone)]
+pub struct PrincipalCollectionSet(#[xml(ty = "untagged")] pub(super) HrefElement);
diff --git a/crates/dav/src/resource/principal_uri.rs b/crates/dav/src/resource/principal_uri.rs
index fe3c1b2..5c1845f 100644
--- a/crates/dav/src/resource/principal_uri.rs
+++ b/crates/dav/src/resource/principal_uri.rs
@@ -1,3 +1,4 @@
 pub trait PrincipalUri: 'static + Clone + Send + Sync {
+    fn principal_collection(&self) -> String;
     fn principal_uri(&self, principal: &str) -> String;
 }