diff --git a/app/controllers/participants_controller.rb b/app/controllers/participants_controller.rb
index d8b47272..8f0de7a3 100644
--- a/app/controllers/participants_controller.rb
+++ b/app/controllers/participants_controller.rb
@@ -4,6 +4,7 @@ class ParticipantsController < ApplicationController
   respond_to :html
   load_resource except: :confirm_email
   before_action :verify_owner, :only => [:edit, :update]
+  before_action :coc_agreement_param_as_timestamp, only: [:create, :update]
 
   def index
     respond_to do |format|
@@ -40,7 +41,6 @@ def update
     end
 
     if @participant.update(new_params)
-      create_code_of_conduct_agreement_if_not_exists!
       flash[:notice] = "Profile updated successfully."
       redirect_to participant_path(@participant)
     else
@@ -52,7 +52,6 @@ def update
   def create
     @participant.attributes = participant_params.except(:code_of_conduct_agreement)
     if @participant.save
-      create_code_of_conduct_agreement_if_not_exists!
       @participant.deliver_email_confirmation_instructions!
       flash[:notice] = "Thanks for registering an account. Please check your email to confirm your account."
       redirect_to root_path
@@ -62,15 +61,6 @@ def create
     end
   end
 
-  def create_code_of_conduct_agreement_if_not_exists!
-    if participant_params[:code_of_conduct_agreement] == '1' && @participant.signed_code_of_conduct_for_current_event? == false
-      CodeOfConductAgreement.create!({
-        participant_id: @participant.id,
-        event_id: Event.current_event.id,
-      })
-    end
-  end
-
   def send_confirmation_email
     @participant.deliver_email_confirmation_instructions!
     flash[:notice] = "Confirmation instructions sent! Please check your email."
@@ -95,11 +85,17 @@ def participant_params
       :name, :email, :password,
       :bio,
       :code_of_conduct_agreement,
-      :contact_details
+      :contact_details, :coc_agreed_at
     )
   end
 
   def verify_owner
     redirect_to participant_path(@participant) if @participant != current_participant
   end
+
+  def coc_agreement_param_as_timestamp
+    if params[:participant][:code_of_conduct_agreement] == '1'
+      params[:participant][:coc_agreed_at] = Time.current
+    end
+  end
 end
diff --git a/app/controllers/sessions_controller.rb b/app/controllers/sessions_controller.rb
index 6068295c..2880a638 100644
--- a/app/controllers/sessions_controller.rb
+++ b/app/controllers/sessions_controller.rb
@@ -78,11 +78,8 @@ def create
   end
 
   def create_code_of_conduct_agreement_if_not_exists!
-    if session_params[:code_of_conduct_agreement] == '1' && @session.participant.signed_code_of_conduct_for_current_event? == false
-      CodeOfConductAgreement.create!({
-        participant_id: @session.participant.id,
-        event_id: Event.current_event.id,
-      })
+    if session_params[:code_of_conduct_agreement] == '1' && !@session.participant.signed_code_of_conduct_for_current_event?
+      current_participant.update!(coc_agreed_at: Time.current)
     end
   end
 
@@ -139,5 +136,4 @@ def sessions_for_event(event)
       .order('created_at desc')
       .distinct
   end
-
 end
diff --git a/app/models/code_of_conduct_agreement.rb b/app/models/code_of_conduct_agreement.rb
deleted file mode 100644
index c8c8baf8..00000000
--- a/app/models/code_of_conduct_agreement.rb
+++ /dev/null
@@ -1,4 +0,0 @@
-class CodeOfConductAgreement < ActiveRecord::Base
-  belongs_to :participant
-  belongs_to :event
-end
diff --git a/app/models/event.rb b/app/models/event.rb
index 5ea49b94..563bc60e 100644
--- a/app/models/event.rb
+++ b/app/models/event.rb
@@ -9,7 +9,6 @@ class NotEnoughRoomsError < StandardError; end
   has_many :categories, through: :event_categories
 
   has_many :presenter_timeslot_restrictions, :through => :timeslots
-  has_many :code_of_conduct_agreements, dependent: :destroy
 
   # Careful! Large joins here; use with caution:
   has_many :attendances, through: :sessions
diff --git a/app/models/participant.rb b/app/models/participant.rb
index 724e52dd..aa0a1d74 100644
--- a/app/models/participant.rb
+++ b/app/models/participant.rb
@@ -5,7 +5,6 @@ class Participant < ActiveRecord::Base
   has_many :presentations
   has_many :sessions_presenting, :through => :presentations, :source => :session
   has_many :presenter_timeslot_restrictions, dependent: :destroy
-  has_many :code_of_conduct_agreements, dependent: :destroy
 
   validates :name, presence: true
   validates :email, presence: true
@@ -82,12 +81,7 @@ def deliver_password_reset_instructions!
   end
 
   def signed_code_of_conduct_for_current_event?
-    return false unless Event.current_event
-
-    CodeOfConductAgreement.where({
-      participant_id: id,
-      event_id: Event.current_event.id,
-    }).exists?
+    coc_agreed_at.present?
   end
 
   def attending_session?(session)
diff --git a/db/migrate/20260520012517_add_coc_agreed_at_to_participants.rb b/db/migrate/20260520012517_add_coc_agreed_at_to_participants.rb
new file mode 100644
index 00000000..6130eae1
--- /dev/null
+++ b/db/migrate/20260520012517_add_coc_agreed_at_to_participants.rb
@@ -0,0 +1,5 @@
+class AddCocAgreedAtToParticipants < ActiveRecord::Migration[7.2]
+  def change
+    add_column :participants, :coc_agreed_at, :datetime
+  end
+end
diff --git a/db/migrate/20260521194947_drop_code_of_conduct_agreements.rb b/db/migrate/20260521194947_drop_code_of_conduct_agreements.rb
new file mode 100644
index 00000000..72a04ae3
--- /dev/null
+++ b/db/migrate/20260521194947_drop_code_of_conduct_agreements.rb
@@ -0,0 +1,16 @@
+class DropCodeOfConductAgreements < ActiveRecord::Migration[7.2]
+  def up
+    drop_table :code_of_conduct_agreements
+  end
+
+  def down
+    create_table :code_of_conduct_agreements do |t|
+      t.bigint :participant_id, null: false
+      t.bigint :event_id, null: false
+      t.timestamps precision: nil, null: false
+    end
+
+    add_index :code_of_conduct_agreements, :event_id
+    add_index :code_of_conduct_agreements, :participant_id
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index 0e322fbb..442fc0e4 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema[7.2].define(version: 2026_03_22_192507) do
+ActiveRecord::Schema[7.2].define(version: 2026_05_21_194947) do
   create_schema "heroku_ext"
 
   # These are extensions that must be enabled in order to support this database
@@ -55,15 +55,6 @@
     t.index ["category_id", "session_id"], name: "index_categorizations_on_category_id_and_session_id", unique: true
   end
 
-  create_table "code_of_conduct_agreements", force: :cascade do |t|
-    t.bigint "participant_id", null: false
-    t.bigint "event_id", null: false
-    t.datetime "created_at", precision: nil, null: false
-    t.datetime "updated_at", precision: nil, null: false
-    t.index ["event_id"], name: "index_code_of_conduct_agreements_on_event_id"
-    t.index ["participant_id"], name: "index_code_of_conduct_agreements_on_participant_id"
-  end
-
   create_table "event_categories", force: :cascade do |t|
     t.bigint "event_id", null: false
     t.bigint "category_id", null: false
@@ -114,6 +105,7 @@
     t.datetime "email_confirmed_at", precision: nil
     t.integer "presentations_count", default: 0
     t.integer "attendances_count", default: 0
+    t.datetime "coc_agreed_at"
     t.index ["email"], name: "index_participants_on_email", unique: true
     t.index ["perishable_token"], name: "index_participants_on_perishable_token"
   end
diff --git a/lib/tasks/app.rake b/lib/tasks/app.rake
index aae3860d..5f8533ac 100644
--- a/lib/tasks/app.rake
+++ b/lib/tasks/app.rake
@@ -517,6 +517,7 @@ namespace :app do
       participant.email = FFaker::Internet.safe_email
       participant.password = 'password'
       participant.bio = FFaker::Lorem.paragraph if [true, false].sample
+      participant.coc_agreed_at = Time.current
       participant.save!
       progress.increment
     end
diff --git a/lib/tasks/backfill.rake b/lib/tasks/backfill.rake
new file mode 100644
index 00000000..a7c6af99
--- /dev/null
+++ b/lib/tasks/backfill.rake
@@ -0,0 +1,16 @@
+namespace :backfill do
+
+  desc 'backfill coc_agreed_at for participants who have already accepted'
+  task coc_agreed_at: :environment do
+    ActiveRecord::Base.connection.execute(<<~SQL)
+      UPDATE participants
+      SET coc_agreed_at = coc.created_at
+      FROM (
+        SELECT DISTINCT ON (participant_id) participant_id, created_at
+        FROM code_of_conduct_agreements
+      ) AS coc
+      WHERE participants.id = coc.participant_id
+      AND participants.coc_agreed_at IS NULL
+    SQL
+  end
+end
\ No newline at end of file
diff --git a/spec/controllers/participants_controller_spec.rb b/spec/controllers/participants_controller_spec.rb
index 3633eea5..0425f31d 100644
--- a/spec/controllers/participants_controller_spec.rb
+++ b/spec/controllers/participants_controller_spec.rb
@@ -45,6 +45,25 @@
       expect(response).to render_template(:new)
       expect(flash[:error]).to eq "There was a problem creating your account."
     end
+
+    it "does not set coc_agreed_at on the participant when the user has not signed the code of conduct" do
+      post :create, params: { participant:  { name: 'Alan Turing',
+                                              email: 'tapewriter@example.org',
+                                              password: 'infinite-memory',
+                                              code_of_conduct_agreement: '0'
+                                            }
+                            }
+      expect(Participant.find_by(email: 'tapewriter@example.org').coc_agreed_at).to be_nil
+    end
+    it "sets coc_agreed_at on the participant when the user has signed the code of conduct" do
+      post :create, params: { participant:  { name: 'Alan Turing',
+                                              email: 'tapewriter@example.org',
+                                              password: 'infinite-memory',
+                                              code_of_conduct_agreement: '1'
+                                            }
+                            }
+      expect(Participant.find_by(email: 'tapewriter@example.org').coc_agreed_at).not_to be_nil
+    end
   end
 
   describe "#show" do
@@ -137,6 +156,14 @@
         expect(response).to redirect_to participant_path(joe)
         expect(joe.reload.name).to eq 'schmoe, joe'
       end
+      it "does not set coc_agreed_at on the participant when the user has not signed the code of conduct" do
+        put :update, params:  { id: joe,  participant:  { name: 'Alan Turing', code_of_conduct_agreement: '0' } }
+        expect(joe.reload.coc_agreed_at).to be_nil
+      end
+      it "sets coc_agreed_at on the participant when the user has signed the code of conduct" do
+        put :update, params:  { id: joe,  participant:  { code_of_conduct_agreement: '1' } }
+        expect(joe.reload.coc_agreed_at).not_to be_nil
+      end
 
       describe "more attributes are not required" do
         it "should be successful" do
diff --git a/spec/controllers/presentations_controller_spec.rb b/spec/controllers/presentations_controller_spec.rb
index d2493c12..3fe11228 100644
--- a/spec/controllers/presentations_controller_spec.rb
+++ b/spec/controllers/presentations_controller_spec.rb
@@ -20,10 +20,7 @@
 
     context "when the user is found by id" do
       it "should be successful when the user has signed the code of conduct" do
-        CodeOfConductAgreement.create!({
-          participant_id: participant.id,
-          event_id: Event.current_event.id,
-        })
+        participant.update!(coc_agreed_at: Time.current)
 
         expect {
           post :create, params: { session_id: session, id: participant.id }
@@ -41,10 +38,7 @@
 
     context "when the user is found by name" do
       it "should be successful when the user has signed the code of conduct" do
-        CodeOfConductAgreement.create!({
-          participant_id: participant.id,
-          event_id: Event.current_event.id,
-        })
+        participant.update!(coc_agreed_at: Time.current)
 
         expect {
           post :create, params: { session_id: session, name: participant.name }
diff --git a/spec/controllers/sessions_controller_spec.rb b/spec/controllers/sessions_controller_spec.rb
index 13b19981..801353e0 100644
--- a/spec/controllers/sessions_controller_spec.rb
+++ b/spec/controllers/sessions_controller_spec.rb
@@ -138,6 +138,29 @@
           expect(assigns[:session].category_ids).to include category.id
           expect(flash[:notice]).to eq "Thanks for adding your session."
         end
+        it "should sign code of conduct if param is present" do
+          expect {
+            post :create, params: { session:  { title: "new title",
+                                                description: "new description",
+                                                category_ids: [category.id],
+                                                level_id: "2",
+                                                code_of_conduct_agreement:  "1",
+                                              }
+                                  }
+          }.to change { Session.count }.by(1)
+          expect(user.reload.coc_agreed_at).not_to be_nil
+        end
+        it "should not sign code of conduct if param is not present" do
+          expect {
+            post :create, params: { session:  { title: "new title",
+                                                description: "new description",
+                                                category_ids: [category.id],
+                                                level_id: "2",
+                                              }
+                                  }
+          }.to change { Session.count }.by(1)
+          expect(user.reload.coc_agreed_at).to be_nil
+        end
       end
 
       context "with invalid values" do