diff --git a/src/libraries/System.Security.Claims/ref/System.Security.Claims.cs b/src/libraries/System.Security.Claims/ref/System.Security.Claims.cs
index 4bc8d68fd834a5..2d3b6bd25df300 100644
--- a/src/libraries/System.Security.Claims/ref/System.Security.Claims.cs
+++ b/src/libraries/System.Security.Claims/ref/System.Security.Claims.cs
@@ -41,11 +41,11 @@ public ClaimsIdentity(System.Collections.Generic.IEnumerable<System.Security.Cla
         public ClaimsIdentity(System.Collections.Generic.IEnumerable<System.Security.Claims.Claim>? claims, string? authenticationType) { }
         public ClaimsIdentity(System.Collections.Generic.IEnumerable<System.Security.Claims.Claim>? claims, string? authenticationType, string? nameType, string? roleType) { }
         public ClaimsIdentity(System.IO.BinaryReader reader) { }
-        [System.ObsoleteAttribute("This API supports obsolete formatter-based serialization. It should not be called or extended by application code.", DiagnosticId = "SYSLIB0051", UrlFormat = "https://aka.ms/dotnet-warnings/{0}")]
         [System.ComponentModel.EditorBrowsableAttribute(System.ComponentModel.EditorBrowsableState.Never)]
+        [System.ObsoleteAttribute("This API supports obsolete formatter-based serialization. It should not be called or extended by application code.", DiagnosticId="SYSLIB0051", UrlFormat="https://aka.ms/dotnet-warnings/{0}")]
         protected ClaimsIdentity(System.Runtime.Serialization.SerializationInfo info) { }
-        [System.ObsoleteAttribute("This API supports obsolete formatter-based serialization. It should not be called or extended by application code.", DiagnosticId = "SYSLIB0051", UrlFormat = "https://aka.ms/dotnet-warnings/{0}")]
         [System.ComponentModel.EditorBrowsableAttribute(System.ComponentModel.EditorBrowsableState.Never)]
+        [System.ObsoleteAttribute("This API supports obsolete formatter-based serialization. It should not be called or extended by application code.", DiagnosticId="SYSLIB0051", UrlFormat="https://aka.ms/dotnet-warnings/{0}")]
         protected ClaimsIdentity(System.Runtime.Serialization.SerializationInfo info, System.Runtime.Serialization.StreamingContext context) { }
         protected ClaimsIdentity(System.Security.Claims.ClaimsIdentity other) { }
         public ClaimsIdentity(System.Security.Principal.IIdentity? identity) { }
@@ -84,8 +84,8 @@ public partial class ClaimsPrincipal : System.Security.Principal.IPrincipal
         public ClaimsPrincipal() { }
         public ClaimsPrincipal(System.Collections.Generic.IEnumerable<System.Security.Claims.ClaimsIdentity> identities) { }
         public ClaimsPrincipal(System.IO.BinaryReader reader) { }
-        [System.ObsoleteAttribute("This API supports obsolete formatter-based serialization. It should not be called or extended by application code.", DiagnosticId = "SYSLIB0051", UrlFormat = "https://aka.ms/dotnet-warnings/{0}")]
         [System.ComponentModel.EditorBrowsableAttribute(System.ComponentModel.EditorBrowsableState.Never)]
+        [System.ObsoleteAttribute("This API supports obsolete formatter-based serialization. It should not be called or extended by application code.", DiagnosticId="SYSLIB0051", UrlFormat="https://aka.ms/dotnet-warnings/{0}")]
         protected ClaimsPrincipal(System.Runtime.Serialization.SerializationInfo info, System.Runtime.Serialization.StreamingContext context) { }
         public ClaimsPrincipal(System.Security.Principal.IIdentity identity) { }
         public ClaimsPrincipal(System.Security.Principal.IPrincipal principal) { }
diff --git a/src/libraries/System.Security.Claims/src/System/Security/Claims/ClaimsIdentity.cs b/src/libraries/System.Security.Claims/src/System/Security/Claims/ClaimsIdentity.cs
index 9733ca86ff10b9..c928dd88501eba 100644
--- a/src/libraries/System.Security.Claims/src/System/Security/Claims/ClaimsIdentity.cs
+++ b/src/libraries/System.Security.Claims/src/System/Security/Claims/ClaimsIdentity.cs
@@ -3,6 +3,7 @@
 
 using System.Collections.Generic;
 using System.ComponentModel;
+using System.Diagnostics;
 using System.IO;
 using System.Runtime.Serialization;
 using System.Security.Principal;
@@ -12,6 +13,8 @@ namespace System.Security.Claims
     /// <summary>
     /// An Identity that is represented by a set of claims.
     /// </summary>
+    [DebuggerDisplay("{DebuggerToString(),nq}")]
+    [DebuggerTypeProxy(typeof(ClaimsIdentityDebugProxy))]
     public class ClaimsIdentity : IIdentity
     {
         private enum SerializationMask
@@ -933,5 +936,38 @@ protected virtual void GetObjectData(SerializationInfo info, StreamingContext co
         {
             throw new PlatformNotSupportedException();
         }
+
+        internal string DebuggerToString()
+        {
+            // DebuggerDisplayAttribute is inherited. Use virtual members instead of private fields to gather data.
+            int claimsCount = 0;
+            foreach (Claim item in Claims)
+            {
+                claimsCount++;
+            }
+
+            return $"Identity Name = {Name ?? "(null)"}, IsAuthenticated = {IsAuthenticated}, Claims Count = {claimsCount}";
+        }
+
+        private sealed class ClaimsIdentityDebugProxy
+        {
+            private readonly ClaimsIdentity _identity;
+
+            public ClaimsIdentityDebugProxy(ClaimsIdentity identity)
+            {
+                _identity = identity;
+            }
+
+            public ClaimsIdentity? Actor => _identity.Actor;
+            public string? AuthenticationType => _identity.AuthenticationType;
+            public object? BootstrapContext => _identity.BootstrapContext;
+            // List type has a friendly debugger view
+            public List<Claim> Claims => new List<Claim>(_identity.Claims);
+            public bool IsAuthenticated => _identity.IsAuthenticated;
+            public string? Label => _identity.Label;
+            public string? Name => _identity.Name;
+            public string NameClaimType => _identity.NameClaimType;
+            public string RoleClaimType => _identity.RoleClaimType;
+        }
     }
 }
diff --git a/src/libraries/System.Security.Claims/src/System/Security/Claims/ClaimsPrincipal.cs b/src/libraries/System.Security.Claims/src/System/Security/Claims/ClaimsPrincipal.cs
index a423bfa4ce4712..1e1efd8eba6268 100644
--- a/src/libraries/System.Security.Claims/src/System/Security/Claims/ClaimsPrincipal.cs
+++ b/src/libraries/System.Security.Claims/src/System/Security/Claims/ClaimsPrincipal.cs
@@ -3,6 +3,7 @@
 
 using System.Collections.Generic;
 using System.ComponentModel;
+using System.Diagnostics;
 using System.IO;
 using System.Runtime.Serialization;
 using System.Security.Principal;
@@ -13,6 +14,8 @@ namespace System.Security.Claims
     /// <summary>
     /// Concrete IPrincipal supporting multiple claims-based identities
     /// </summary>
+    [DebuggerDisplay("{DebuggerToString(),nq}")]
+    [DebuggerTypeProxy(typeof(ClaimsPrincipalDebugProxy))]
     public class ClaimsPrincipal : IPrincipal
     {
         private enum SerializationMask
@@ -567,5 +570,44 @@ protected virtual void GetObjectData(SerializationInfo info, StreamingContext co
         {
             throw new PlatformNotSupportedException();
         }
+
+        private string DebuggerToString()
+        {
+            // DebuggerDisplayAttribute is inherited. Use virtual members instead of private fields to gather data.
+            int identitiesCount = 0;
+            foreach (ClaimsIdentity items in Identities)
+            {
+                identitiesCount++;
+            }
+
+            int claimsCount = 0;
+            foreach (Claim item in Claims)
+            {
+                claimsCount++;
+            }
+
+            // Return debug string optimized for the case of one identity.
+            if (identitiesCount == 1 && Identity is ClaimsIdentity claimsIdentity)
+            {
+                return $"Principal {claimsIdentity.DebuggerToString()}";
+            }
+
+            return $"Principal Identities Count: {identitiesCount}, Claims Count: {claimsCount}";
+        }
+
+        private sealed class ClaimsPrincipalDebugProxy
+        {
+            private readonly ClaimsPrincipal _principal;
+
+            public ClaimsPrincipalDebugProxy(ClaimsPrincipal principal)
+            {
+                _principal = principal;
+            }
+
+            // List type has a friendly debugger view
+            public List<Claim> Claims => new List<Claim>(_principal.Claims);
+            public List<ClaimsIdentity> Identities => new List<ClaimsIdentity>(_principal.Identities);
+            public IIdentity? Identity => _principal.Identity;
+        }
     }
 }