diff --git a/config/sidekiq_queues.yml b/config/sidekiq_queues.yml
index d950a275c85e677cd27b2958c2259d5b6d4d3e13..88c320f34a975412fb7fa321e4166dd8981ef025 100644
--- a/config/sidekiq_queues.yml
+++ b/config/sidekiq_queues.yml
@@ -489,6 +489,10 @@
   - 1
 - - gitlab_subscriptions_seat_assignments_group_links_create_or_update_seats
   - 1
+- - gitlab_subscriptions_seat_assignments_member_transfers_create_group_seats
+  - 1
+- - gitlab_subscriptions_seat_assignments_member_transfers_create_project_seats
+  - 1
 - - gitlab_subscriptions_self_managed_duo_core_todo_notification
   - 1
 - - gitlab_subscriptions_trials_apply_trial
diff --git a/ee/app/workers/all_queues.yml b/ee/app/workers/all_queues.yml
index 694b83dcdd42ded3c43f0dbfb23add9eb7cd8aa4..87ecf9e69b03e5bb1c3acbc0fb36b5e9f6876452 100644
--- a/ee/app/workers/all_queues.yml
+++ b/ee/app/workers/all_queues.yml
@@ -2443,6 +2443,26 @@
   :idempotent: true
   :tags: []
   :queue_namespace:
+- :name: gitlab_subscriptions_seat_assignments_member_transfers_create_group_seats
+  :worker_name: GitlabSubscriptions::SeatAssignments::MemberTransfers::CreateGroupSeatsWorker
+  :feature_category: :seat_cost_management
+  :has_external_dependencies: false
+  :urgency: :low
+  :resource_boundary: :unknown
+  :weight: 1
+  :idempotent: true
+  :tags: []
+  :queue_namespace:
+- :name: gitlab_subscriptions_seat_assignments_member_transfers_create_project_seats
+  :worker_name: GitlabSubscriptions::SeatAssignments::MemberTransfers::CreateProjectSeatsWorker
+  :feature_category: :seat_cost_management
+  :has_external_dependencies: false
+  :urgency: :low
+  :resource_boundary: :unknown
+  :weight: 1
+  :idempotent: true
+  :tags: []
+  :queue_namespace:
 - :name: gitlab_subscriptions_self_managed_duo_core_todo_notification
   :worker_name: GitlabSubscriptions::SelfManaged::DuoCoreTodoNotificationWorker
   :feature_category: :acquisition
diff --git a/ee/app/workers/gitlab_subscriptions/seat_assignments/member_transfers/base_create_seats_worker.rb b/ee/app/workers/gitlab_subscriptions/seat_assignments/member_transfers/base_create_seats_worker.rb
new file mode 100644
index 0000000000000000000000000000000000000000..4ccca787a695053478a0a6c2ed16a2ede1045665
--- /dev/null
+++ b/ee/app/workers/gitlab_subscriptions/seat_assignments/member_transfers/base_create_seats_worker.rb
@@ -0,0 +1,50 @@
+# frozen_string_literal: true
+
+# rubocop:disable Scalability/IdempotentWorker -- Idempotent declaration in child
+module GitlabSubscriptions
+  module SeatAssignments
+    module MemberTransfers
+      class BaseCreateSeatsWorker
+        BATCH_SIZE = 100
+
+        def perform(source_id)
+          source = find_source_by_id(source_id)
+          return unless source
+
+          create_missing_seat_assignments(source)
+        end
+
+        private
+
+        def create_missing_seat_assignments(source)
+          namespace_id = source.root_ancestor.id
+          organization_id = source.root_ancestor.organization_id
+
+          collect_user_ids(source).each_batch(of: BATCH_SIZE) do |users|
+            seat_assignments = users.pluck_user_ids.map do |user_id|
+              {
+                namespace_id: namespace_id,
+                user_id: user_id,
+                organization_id: organization_id
+              }
+            end
+
+            ::GitlabSubscriptions::SeatAssignment.insert_all(
+              seat_assignments,
+              unique_by: [:namespace_id, :user_id]
+            )
+          end
+        end
+
+        def collect_user_ids(_source)
+          raise NotImplementedError
+        end
+
+        def find_source_by_id(_source_id)
+          raise NotImplementedError
+        end
+      end
+    end
+  end
+end
+# rubocop:enable Scalability/IdempotentWorker
diff --git a/ee/app/workers/gitlab_subscriptions/seat_assignments/member_transfers/create_group_seats_worker.rb b/ee/app/workers/gitlab_subscriptions/seat_assignments/member_transfers/create_group_seats_worker.rb
new file mode 100644
index 0000000000000000000000000000000000000000..dee6c1ac8d6b494221d0042c959939016469e3eb
--- /dev/null
+++ b/ee/app/workers/gitlab_subscriptions/seat_assignments/member_transfers/create_group_seats_worker.rb
@@ -0,0 +1,30 @@
+# frozen_string_literal: true
+
+module GitlabSubscriptions
+  module SeatAssignments
+    module MemberTransfers
+      class CreateGroupSeatsWorker < BaseCreateSeatsWorker
+        include ApplicationWorker
+
+        feature_category :seat_cost_management
+        data_consistency :delayed
+        urgency :low
+
+        defer_on_database_health_signal :gitlab_main,
+          [:subscription_seat_assignments, :members], 10.minutes
+
+        idempotent!
+
+        private
+
+        def find_source_by_id(group_id)
+          Group.find_by_id(group_id)
+        end
+
+        def collect_user_ids(group)
+          Member.for_self_and_descendants(group)
+        end
+      end
+    end
+  end
+end
diff --git a/ee/app/workers/gitlab_subscriptions/seat_assignments/member_transfers/create_project_seats_worker.rb b/ee/app/workers/gitlab_subscriptions/seat_assignments/member_transfers/create_project_seats_worker.rb
new file mode 100644
index 0000000000000000000000000000000000000000..81ca2da14fabfdc520ffd4f658832d17c27e2013
--- /dev/null
+++ b/ee/app/workers/gitlab_subscriptions/seat_assignments/member_transfers/create_project_seats_worker.rb
@@ -0,0 +1,30 @@
+# frozen_string_literal: true
+
+module GitlabSubscriptions
+  module SeatAssignments
+    module MemberTransfers
+      class CreateProjectSeatsWorker < BaseCreateSeatsWorker
+        include ApplicationWorker
+
+        feature_category :seat_cost_management
+        data_consistency :delayed
+        urgency :low
+
+        defer_on_database_health_signal :gitlab_main,
+          [:subscription_seat_assignments, :members], 10.minutes
+
+        idempotent!
+
+        private
+
+        def find_source_by_id(project_id)
+          Project.find_by_id(project_id)
+        end
+
+        def collect_user_ids(project)
+          project.project_members
+        end
+      end
+    end
+  end
+end
diff --git a/ee/spec/workers/gitlab_subscriptions/seat_assignments/member_transfers/base_create_seats_worker_spec.rb b/ee/spec/workers/gitlab_subscriptions/seat_assignments/member_transfers/base_create_seats_worker_spec.rb
new file mode 100644
index 0000000000000000000000000000000000000000..e3b53f266372c956e676c16297675efb118a6e08
--- /dev/null
+++ b/ee/spec/workers/gitlab_subscriptions/seat_assignments/member_transfers/base_create_seats_worker_spec.rb
@@ -0,0 +1,19 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe GitlabSubscriptions::SeatAssignments::MemberTransfers::BaseCreateSeatsWorker, :saas, feature_category: :seat_cost_management do
+  let(:worker) { described_class.new }
+
+  describe '#collect_user_ids' do
+    it 'raises NotImplementedError' do
+      expect { worker.send(:collect_user_ids, double) }.to raise_error(NotImplementedError)
+    end
+  end
+
+  describe '#find_source_by_id' do
+    it 'raises NotImplementedError' do
+      expect { worker.send(:find_source_by_id, double) }.to raise_error(NotImplementedError)
+    end
+  end
+end
diff --git a/ee/spec/workers/gitlab_subscriptions/seat_assignments/member_transfers/create_group_seats_worker_spec.rb b/ee/spec/workers/gitlab_subscriptions/seat_assignments/member_transfers/create_group_seats_worker_spec.rb
new file mode 100644
index 0000000000000000000000000000000000000000..cb49a57ef2e2a8b5b7d7bc3a5dfe1268ea22476d
--- /dev/null
+++ b/ee/spec/workers/gitlab_subscriptions/seat_assignments/member_transfers/create_group_seats_worker_spec.rb
@@ -0,0 +1,187 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe GitlabSubscriptions::SeatAssignments::MemberTransfers::CreateGroupSeatsWorker, :saas, feature_category: :seat_cost_management do
+  let(:worker) { described_class.new }
+  let_it_be(:user) { create(:user) }
+  let_it_be(:user_2) { create(:user) }
+  let_it_be(:user_3) { create(:user) }
+
+  it_behaves_like 'worker with data consistency', described_class, data_consistency: :delayed
+
+  it_behaves_like 'an idempotent worker' do
+    let_it_be(:group) { create(:group) }
+
+    before do
+      create(:group_member, group: group, user: user)
+    end
+
+    let(:job_args) { [group.id] }
+  end
+
+  describe '#perform' do
+    context 'when the group is nil' do
+      it 'does nothing' do
+        expect(worker).not_to receive(:create_missing_seat_assignments)
+
+        worker.perform(non_existing_record_id)
+      end
+    end
+
+    context 'with a root group' do
+      let_it_be_with_refind(:group) { create(:group) }
+
+      before do
+        create(:gitlab_subscription_seat_assignment, user: user, namespace: group)
+      end
+
+      context 'when group namespace has missing seats' do
+        before do
+          create(:group_member, group: group, user: user)
+          create(:group_member, group: group, user: user_2)
+          create(:group_member, group: group, user: user_3)
+        end
+
+        it 'creates seat assignments for the missing users' do
+          worker.perform(group.id)
+
+          expect(
+            GitlabSubscriptions::SeatAssignment.by_namespace(group).pluck(:user_id)
+          ).to include(user_2.id, user_3.id)
+        end
+
+        it 'creates seat assignments for all members' do
+          worker.perform(group.id)
+
+          expect(
+            GitlabSubscriptions::SeatAssignment.by_namespace(group).pluck(:user_id)
+          ).to match_array([user.id, user_2.id, user_3.id])
+        end
+      end
+
+      context 'when a group namespace does not have missing seat assignments' do
+        before do
+          create(:group_member, group: group, user: user)
+          create(:group_member, group: group, user: user_2)
+          create(:group_member, group: group, user: user_3)
+          create(:gitlab_subscription_seat_assignment, :active, user: user_2, namespace: group)
+          create(:gitlab_subscription_seat_assignment, :active, user: user_3, namespace: group)
+        end
+
+        it 'does not create seat assignments' do
+          expect do
+            worker.perform(group.id)
+          end.not_to change { GitlabSubscriptions::SeatAssignment.by_namespace(group).pluck(:user_id) }
+        end
+      end
+
+      context 'when a root group has a project with members' do
+        let_it_be(:project) { create(:project, namespace: group) }
+
+        before do
+          create(:group_member, group: group, user: user)
+          create(:project_member, project: project, user: user_2)
+          create(:project_member, project: project, user: user_3)
+        end
+
+        it 'creates seat assignments for the project members' do
+          worker.perform(group.id)
+
+          expect(
+            GitlabSubscriptions::SeatAssignment.by_namespace(group).pluck(:user_id)
+          ).to include(user_2.id, user_3.id)
+        end
+      end
+
+      context 'when a group has a parent root group' do
+        let_it_be_with_refind(:transferred_group) { create(:group, parent: group) }
+        let_it_be(:user_4) { create(:user) }
+
+        before do
+          create(:group_member, group: group, user: user_4)
+          create(:group_member, group: transferred_group, user: user_2)
+          create(:group_member, group: transferred_group, user: user_3)
+        end
+
+        it 'creates seat assignments in the root group for the members of the group being passed' do
+          worker.perform(transferred_group.id)
+
+          expect(
+            GitlabSubscriptions::SeatAssignment.by_namespace(group).pluck(:user_id)
+          ).to match_array([user.id, user_2.id, user_3.id])
+        end
+
+        it 'does not create seats for members of the root group if a child group is passed' do
+          worker.perform(transferred_group.id)
+
+          expect(
+            GitlabSubscriptions::SeatAssignment.by_namespace(group).pluck(:user_id)
+          ).not_to include(user_4.id)
+        end
+
+        it 'does not assign seats to the child group' do
+          worker.perform(transferred_group.id)
+
+          expect(
+            GitlabSubscriptions::SeatAssignment.by_namespace(transferred_group)
+          ).to be_empty
+        end
+      end
+
+      context 'with nested hierarchy' do
+        let_it_be(:child_group_a) { create(:group, parent: group) }
+        let_it_be(:child_group_b) { create(:group, parent: group) }
+        let_it_be(:child_group_c) { create(:group, parent: child_group_a) }
+        let_it_be(:user_4) { create(:user) }
+
+        before do
+          create(:group_member, group: group, user: user)
+          create(:group_member, group: child_group_a, user: user_2)
+          create(:group_member, group: child_group_b, user: user_3)
+          create(:group_member, group: child_group_c, user: user_4)
+        end
+
+        context 'when a leaf group is passed' do
+          it 'creates seat assignments in the root group only for the members of the leaf group' do
+            worker.perform(child_group_c.id)
+
+            expect(
+              GitlabSubscriptions::SeatAssignment.by_namespace(group).pluck(:user_id)
+            ).to match_array([user.id, user_4.id])
+          end
+        end
+
+        context 'when a subhierarchy is passed' do
+          it 'creates seat assignments in the root group only for members of the subhierarchy' do
+            worker.perform(child_group_a.id)
+
+            expect(
+              GitlabSubscriptions::SeatAssignment.by_namespace(group).pluck(:user_id)
+            ).to match_array([user.id, user_2.id, user_4.id])
+          end
+        end
+
+        context 'when a sibling group is passed' do
+          it 'creates seat assignments in the root group only for the members of sibling' do
+            worker.perform(child_group_b.id)
+
+            expect(
+              GitlabSubscriptions::SeatAssignment.by_namespace(group).pluck(:user_id)
+            ).to match_array([user.id, user_3.id])
+          end
+        end
+
+        context 'when the root group is passed' do
+          it 'creates seat assignments in the root group for all members of the hierarchy' do
+            worker.perform(group.id)
+
+            expect(
+              GitlabSubscriptions::SeatAssignment.by_namespace(group).pluck(:user_id)
+            ).to match_array([user.id, user_2.id, user_3.id, user_4.id])
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/ee/spec/workers/gitlab_subscriptions/seat_assignments/member_transfers/create_project_seats_worker_spec.rb b/ee/spec/workers/gitlab_subscriptions/seat_assignments/member_transfers/create_project_seats_worker_spec.rb
new file mode 100644
index 0000000000000000000000000000000000000000..8255beac17cfa9bc8f1a95b5676c70bbb7eeea5f
--- /dev/null
+++ b/ee/spec/workers/gitlab_subscriptions/seat_assignments/member_transfers/create_project_seats_worker_spec.rb
@@ -0,0 +1,113 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe GitlabSubscriptions::SeatAssignments::MemberTransfers::CreateProjectSeatsWorker, :saas, feature_category: :seat_cost_management do
+  let(:worker) { described_class.new }
+  let_it_be(:user) { create(:user, :with_namespace) }
+  let_it_be(:user_2) { create(:user) }
+  let_it_be(:user_3) { create(:user) }
+
+  it_behaves_like 'worker with data consistency', described_class, data_consistency: :delayed
+
+  it_behaves_like 'an idempotent worker' do
+    let_it_be(:project) { create(:project) }
+
+    before do
+      create(:project_member, project: project, user: user)
+    end
+
+    let(:job_args) { [project.id] }
+  end
+
+  describe '#perform' do
+    it 'does nothing when there is no project' do
+      expect(worker).not_to receive(:create_missing_seat_assignments)
+
+      worker.perform(non_existing_record_id)
+    end
+
+    context 'when the project root namespace is a user namespace' do
+      let_it_be(:project) { create(:project, namespace: user.namespace) }
+
+      before do
+        create(:project_member, project: project, user: user_2)
+        create(:project_member, project: project, user: user_3)
+        create(:gitlab_subscription_seat_assignment, user: user, namespace: project.namespace)
+      end
+
+      it 'creates seat assignments in the user namespace only for members of the project' do
+        worker.perform(project.id)
+
+        expect(
+          GitlabSubscriptions::SeatAssignment.by_namespace(project.namespace).pluck(:user_id)
+        ).to match_array([user.id, user_2.id, user_3.id])
+      end
+
+      context 'when a user namespace does not have missing seat assignments' do
+        before do
+          create(:gitlab_subscription_seat_assignment, user: user_2, namespace: project.namespace)
+          create(:gitlab_subscription_seat_assignment, user: user_3, namespace: project.namespace)
+        end
+
+        it 'does not create duplicates if seat assignments are already reconciled' do
+          expect do
+            worker.perform(project.id)
+          end.not_to change { GitlabSubscriptions::SeatAssignment.by_namespace(project.namespace).count }
+        end
+      end
+    end
+
+    context 'when the project root namespace is a group' do
+      let_it_be_with_refind(:group) { create(:group) }
+      let_it_be(:project) { create(:project, namespace: group) }
+
+      before do
+        create(:group_member, group: group, user: user)
+        create(:project_member, project: project, user: user_2)
+        create(:project_member, project: project, user: user_3)
+      end
+
+      it 'creates seat assignments in the root group only for the members of the project' do
+        worker.perform(project.id)
+
+        expect(
+          GitlabSubscriptions::SeatAssignment.by_namespace(group).pluck(:user_id)
+        ).to match_array([user_2.id, user_3.id])
+      end
+
+      context 'when the root group namespace already has seats for the project members' do
+        before do
+          create(:gitlab_subscription_seat_assignment, user: user_2, namespace: group)
+          create(:gitlab_subscription_seat_assignment, user: user_3, namespace: group)
+        end
+
+        it 'does not create duplicate seats' do
+          expect do
+            worker.perform(project.id)
+          end.not_to change { GitlabSubscriptions::SeatAssignment.by_namespace(group).count }
+        end
+      end
+    end
+
+    context 'when the project belongs to a subgroup' do
+      let_it_be_with_refind(:group) { create(:group) }
+      let_it_be(:child_group) { create(:group, parent: group) }
+      let_it_be(:project) { create(:project, namespace: child_group) }
+
+      before do
+        create(:group_member, group: group, user: user)
+        create(:group_member, group: child_group, user: user_2)
+        create(:project_member, project: project, user: user_3)
+      end
+
+      it 'creates seat assignments in the root group only for the members of the project' do
+        worker.perform(project.id)
+
+        expect(
+          GitlabSubscriptions::SeatAssignment.by_namespace(group).pluck(:user_id)
+        ).to match_array([user_3.id])
+      end
+    end
+  end
+end