diff --git a/src/Core/AdminConsole/OrganizationFeatures/OrganizationUsers/InviteUsers/Validation/InviteUserValidationErrorMessages.cs b/src/Core/AdminConsole/OrganizationFeatures/OrganizationUsers/InviteUsers/Validation/InviteUserValidationErrorMessages.cs
index 9d475b1dd6..7d26628da5 100644
--- a/src/Core/AdminConsole/OrganizationFeatures/OrganizationUsers/InviteUsers/Validation/InviteUserValidationErrorMessages.cs
+++ b/src/Core/AdminConsole/OrganizationFeatures/OrganizationUsers/InviteUsers/Validation/InviteUserValidationErrorMessages.cs
@@ -3,13 +3,17 @@
 public static class InviteUserValidationErrorMessages
 {
     public const string CannotAutoScaleOnSelfHostedError = "Cannot autoscale on self-hosted instance.";
-    public const string SeatLimitHasBeenReachedError = "Seat limit has been reached.";
     public const string ProviderBillableSeatLimitError = "Seat limit has been reached. Please contact your provider to add more seats.";
     public const string ProviderResellerSeatLimitError = "Seat limit has been reached. Contact your provider to purchase additional seats.";
     public const string CancelledSubscriptionError = "Cannot autoscale with a canceled subscription.";
     public const string NoPaymentMethodFoundError = "No payment method found.";
     public const string NoSubscriptionFoundError = "No subscription found.";
 
+    // Password Manger Invite Users Error Messages
+    public const string SeatLimitHasBeenReachedError = "Seat limit has been reached.";
+    public const string PlanDoesNotAllowAdditionalSeats = "Plan does not allow additional seats.";
+    public const string PlanOnlyAllowsMaxAdditionalSeats = "Organization plan allows a maximum of {0} additional seats.";
+
     // Secrets Manager Invite Users Error Messages
     public const string OrganizationNoSecretsManager = "Organization has no access to Secrets Manager";
     public const string SecretsManagerSeatLimitReached = "Secrets Manager seat limit has been reached.";
diff --git a/src/Core/AdminConsole/OrganizationFeatures/OrganizationUsers/InviteUsers/Validation/Models/PasswordManagerSubscriptionUpdate.cs b/src/Core/AdminConsole/OrganizationFeatures/OrganizationUsers/InviteUsers/Validation/Models/PasswordManagerSubscriptionUpdate.cs
index aa350a5921..f00c2202b5 100644
--- a/src/Core/AdminConsole/OrganizationFeatures/OrganizationUsers/InviteUsers/Validation/Models/PasswordManagerSubscriptionUpdate.cs
+++ b/src/Core/AdminConsole/OrganizationFeatures/OrganizationUsers/InviteUsers/Validation/Models/PasswordManagerSubscriptionUpdate.cs
@@ -1,5 +1,6 @@
 using Bit.Core.AdminConsole.Models.Business;
 using Bit.Core.AdminConsole.OrganizationFeatures.OrganizationUsers.InviteUsers.Models;
+using Bit.Core.Models.StaticStore;
 
 namespace Bit.Core.AdminConsole.OrganizationFeatures.OrganizationUsers.InviteUsers.Validation.Models;
 
@@ -8,13 +9,13 @@ public class PasswordManagerSubscriptionUpdate
     /// <summary>
     /// Seats the organization has
     /// </summary>
-    public int? Seats { get; private init; }
+    public int? Seats { get; }
 
-    public int? MaxAutoScaleSeats { get; private init; }
+    public int? MaxAutoScaleSeats { get; }
 
-    public int OccupiedSeats { get; private init; }
+    public int OccupiedSeats { get; }
 
-    public int AdditionalSeats { get; private init; }
+    public int AdditionalSeats { get; }
 
     public int? AvailableSeats => Seats - OccupiedSeats;
 
@@ -22,22 +23,25 @@ public class PasswordManagerSubscriptionUpdate
 
     public int? UpdatedSeatTotal => Seats + SeatsRequiredToAdd;
 
-    private PasswordManagerSubscriptionUpdate(int? organizationSeats, int? organizationAutoScaleSeatLimit, int currentSeats, int seatsToAdd)
+    public Plan Plan { get; }
+
+    private PasswordManagerSubscriptionUpdate(int? organizationSeats, int? organizationAutoScaleSeatLimit, int currentSeats, int seatsToAdd, Plan plan)
     {
         Seats = organizationSeats;
         MaxAutoScaleSeats = organizationAutoScaleSeatLimit;
         OccupiedSeats = currentSeats;
         AdditionalSeats = seatsToAdd;
+        Plan = plan;
     }
 
     public static PasswordManagerSubscriptionUpdate Create(OrganizationDto organizationDto, int occupiedSeats, int seatsToAdd)
     {
-        return new PasswordManagerSubscriptionUpdate(organizationDto.Seats, organizationDto.MaxAutoScaleSeats, occupiedSeats, seatsToAdd);
+        return new PasswordManagerSubscriptionUpdate(organizationDto.Seats, organizationDto.MaxAutoScaleSeats, occupiedSeats, seatsToAdd, organizationDto.Plan);
     }
 
     public static PasswordManagerSubscriptionUpdate Create(InviteUserOrganizationValidationRequest refined)
     {
         return new PasswordManagerSubscriptionUpdate(refined.Organization.Seats, refined.Organization.MaxAutoScaleSeats,
-            refined.OccupiedPmSeats, refined.Invites.Length);
+            refined.OccupiedPmSeats, refined.Invites.Length, refined.Organization.Plan);
     }
 }
diff --git a/src/Core/AdminConsole/OrganizationFeatures/OrganizationUsers/InviteUsers/Validation/PasswordManagerInviteUserValidation.cs b/src/Core/AdminConsole/OrganizationFeatures/OrganizationUsers/InviteUsers/Validation/PasswordManagerInviteUserValidation.cs
index 5cb896d784..0ff2145be0 100644
--- a/src/Core/AdminConsole/OrganizationFeatures/OrganizationUsers/InviteUsers/Validation/PasswordManagerInviteUserValidation.cs
+++ b/src/Core/AdminConsole/OrganizationFeatures/OrganizationUsers/InviteUsers/Validation/PasswordManagerInviteUserValidation.cs
@@ -5,8 +5,7 @@ namespace Bit.Core.AdminConsole.OrganizationFeatures.OrganizationUsers.InviteUse
 
 public static class PasswordManagerInviteUserValidation
 {
-
-    // TODO need to add plan validation from AdjustSeatsAsync
+    // NOTE This is only for validating adding users to an organization, not removing
 
     public static ValidationResult<PasswordManagerSubscriptionUpdate> Validate(PasswordManagerSubscriptionUpdate subscriptionUpdate)
     {
@@ -26,6 +25,18 @@ public static class PasswordManagerInviteUserValidation
             return new Invalid<PasswordManagerSubscriptionUpdate>(SeatLimitHasBeenReachedError);
         }
 
+        if (subscriptionUpdate.Plan.PasswordManager.HasAdditionalSeatsOption is false)
+        {
+            return new Invalid<PasswordManagerSubscriptionUpdate>(PlanDoesNotAllowAdditionalSeats);
+        }
+
+        // Apparently MaxAdditionalSeats is never set. Can probably be removed.
+        if (subscriptionUpdate.AdditionalSeats > subscriptionUpdate.Plan.PasswordManager.MaxAdditionalSeats)
+        {
+            return new Invalid<PasswordManagerSubscriptionUpdate>(string.Format(PlanOnlyAllowsMaxAdditionalSeats,
+                subscriptionUpdate.Plan.PasswordManager.MaxAdditionalSeats));
+        }
+
         return new Valid<PasswordManagerSubscriptionUpdate>(subscriptionUpdate);
     }
 }
diff --git a/test/Core.Test/AdminConsole/OrganizationFeatures/OrganizationUsers/InviteUsers/Validation/PasswordManagerInviteUserValidationTests.cs b/test/Core.Test/AdminConsole/OrganizationFeatures/OrganizationUsers/InviteUsers/Validation/PasswordManagerInviteUserValidationTests.cs
index d3645abb58..f4c9a9b1af 100644
--- a/test/Core.Test/AdminConsole/OrganizationFeatures/OrganizationUsers/InviteUsers/Validation/PasswordManagerInviteUserValidationTests.cs
+++ b/test/Core.Test/AdminConsole/OrganizationFeatures/OrganizationUsers/InviteUsers/Validation/PasswordManagerInviteUserValidationTests.cs
@@ -2,6 +2,7 @@
 using Bit.Core.AdminConsole.Models.Business;
 using Bit.Core.AdminConsole.OrganizationFeatures.OrganizationUsers.InviteUsers.Validation;
 using Bit.Core.AdminConsole.OrganizationFeatures.OrganizationUsers.InviteUsers.Validation.Models;
+using Bit.Core.Billing.Enums;
 using Bit.Test.Common.AutoFixture.Attributes;
 using Xunit;
 
@@ -30,6 +31,7 @@ public class PasswordManagerInviteUserValidationTests
     public void Validate_NumberOfSeatsToAddMatchesSeatsAvailable_ShouldReturnValidResult(Organization organization)
     {
         organization.Seats = 8;
+        organization.PlanType = PlanType.EnterpriseAnnually;
         var seatsOccupiedByUsers = 4;
         var additionalSeats = 4;
 
@@ -61,4 +63,23 @@ public class PasswordManagerInviteUserValidationTests
         Assert.Equal(InviteUserValidationErrorMessages.SeatLimitHasBeenReachedError, result.ErrorMessageString);
     }
 
+    [Theory]
+    [BitAutoData]
+    public void Validate_GivenThePlanDoesNotAllowAdditionalSeats_ShouldBeInvalidMessageOfPlanNotAllowingSeats(Organization organization)
+    {
+        organization.Seats = 8;
+        var seatsOccupiedByUsers = 4;
+        var additionalSeats = 4;
+        organization.PlanType = PlanType.Free;
+
+        var organizationDto = OrganizationDto.FromOrganization(organization);
+
+        var subscriptionUpdate = PasswordManagerSubscriptionUpdate.Create(organizationDto, seatsOccupiedByUsers, additionalSeats);
+
+        var result = PasswordManagerInviteUserValidation.Validate(subscriptionUpdate);
+
+        Assert.IsType<Invalid<PasswordManagerSubscriptionUpdate>>(result);
+        Assert.Equal(InviteUserValidationErrorMessages.PlanDoesNotAllowAdditionalSeats, result.ErrorMessageString);
+    }
+
 }