diff --git a/app/forms/edit_phone_form.rb b/app/forms/edit_phone_form.rb
index f014de1462e..4e3b615fdd4 100644
--- a/app/forms/edit_phone_form.rb
+++ b/app/forms/edit_phone_form.rb
@@ -33,6 +33,10 @@ def default_phone_configuration?
     phone_configuration == user.default_phone_configuration
   end
 
+  def one_phone_configured?
+    user.phone_configurations.count == 1
+  end
+
   private
 
   attr_writer :delivery_preference, :make_default_number
diff --git a/app/views/accounts/_phone.html.erb b/app/views/accounts/_phone.html.erb
index 2536b162cc7..a9eaf9bb540 100644
--- a/app/views/accounts/_phone.html.erb
+++ b/app/views/accounts/_phone.html.erb
@@ -10,7 +10,7 @@
       <div class="grid-row grid-gap-2">
         <div class="grid-col-fill">
           <%= PhoneFormatter.format(phone_configuration.phone) %>
-          <% if current_user.default_phone_configuration == phone_configuration %>
+          <% if current_user.default_phone_configuration == phone_configuration && MfaContext.new(current_user).phone_configurations.count > 1 %>
             (<%= I18n.t('account.index.default') %>)
           <% end %>
         </div>
diff --git a/app/views/users/edit_phone/_make_default_number.html.erb b/app/views/users/edit_phone/_make_default_number.html.erb
index 0b68b2faf71..1f553071e31 100644
--- a/app/views/users/edit_phone/_make_default_number.html.erb
+++ b/app/views/users/edit_phone/_make_default_number.html.erb
@@ -1,16 +1,25 @@
 <div class="margin-bottom-4">
   <fieldset class="margin-0 padding-0 border-0">
     <legend class="margin-bottom-1">
-      <%= t('two_factor_authentication.otp_make_default_number.title') %>
+      <% if @edit_phone_form.one_phone_configured? %>
+        <%= t('two_factor_authentication.otp_make_default_number.one_number_title') %>
+      <% else %>
+        <%= t('two_factor_authentication.otp_make_default_number.title') %>
+      <% end %>
     </legend>
-    <p class="margin-top-0 margin-bottom-2" id="otp_make_default_number_instruction">
-      <%= t('two_factor_authentication.otp_make_default_number.instruction') %>
+    <p class="margin-top-0 margin-bottom-2">
+      <% if @edit_phone_form.one_phone_configured? %>
+        <%= t('two_factor_authentication.otp_make_default_number.one_number_instruction') %>
+      <% else %>
+        <%= t('two_factor_authentication.otp_make_default_number.instruction') %>
+      <% end %>
     </p>
     <%= check_box_tag(
           'edit_phone_form[make_default_number]',
           :otp_make_default_number,
           @edit_phone_form.default_phone_configuration?,
           class: 'usa-checkbox__input usa-checkbox__input--bordered',
+          disabled: @edit_phone_form.one_phone_configured?,
         ) %>
     <label
       class="usa-checkbox__label"
diff --git a/config/locales/two_factor_authentication/en.yml b/config/locales/two_factor_authentication/en.yml
index 73fa14a6e52..24a5d123f76 100644
--- a/config/locales/two_factor_authentication/en.yml
+++ b/config/locales/two_factor_authentication/en.yml
@@ -88,9 +88,12 @@ en:
       voice: Phone call
       voice_unsupported: We are unable to call phone numbers in %{location}.
     otp_make_default_number:
-      instruction: Please check the box below if you want this to be the default phone
-        number you receive text messages or phone calls.
+      instruction: Make this phone number the default number where you receive text
+        message or phone calls.
       label: Default phone number
+      one_number_instruction: You must have more than one phone number added to select
+        a default phone number.
+      one_number_title: This is your default number
       title: Make this your default phone number?
     personal_key_fallback:
       question: Don’t have your personal key?
diff --git a/config/locales/two_factor_authentication/es.yml b/config/locales/two_factor_authentication/es.yml
index 120bf3596c9..7ff3718ed30 100644
--- a/config/locales/two_factor_authentication/es.yml
+++ b/config/locales/two_factor_authentication/es.yml
@@ -95,10 +95,12 @@ es:
       voice: Llamada telefónica
       voice_unsupported: No podemos llamar a números de teléfono en %{location}.
     otp_make_default_number:
-      instruction: Marque la casilla a continuación si desea que este sea el teléfono
-        predeterminado número que recibe mensajes de texto o llamadas
-        telefónicas.
+      instruction: Establece este número de teléfono como predeterminado para que
+        recibas en él mensajes de texto o llamadas telefónicas.
       label: Número de teléfono predeterminado
+      one_number_instruction: Debes tener más de un número de teléfono agregado para
+        seleccionar un número de teléfono predeterminado.
+      one_number_title: Este es tu número predeterminado
       title: '¿Es este tu número de teléfono predeterminado?'
     personal_key_fallback:
       question: '¿No tiene su clave personal?'
diff --git a/config/locales/two_factor_authentication/fr.yml b/config/locales/two_factor_authentication/fr.yml
index ed826d49d4d..90486aacf94 100644
--- a/config/locales/two_factor_authentication/fr.yml
+++ b/config/locales/two_factor_authentication/fr.yml
@@ -99,10 +99,12 @@ fr:
       voice_unsupported: Il nous est impossible d’appeler des numéros de téléphone
         dans le %{location}.
     otp_make_default_number:
-      instruction: Veuillez cocher la case ci-dessous si vous voulez que ce soit le
-        téléphone par défaut. numéro que vous recevez des messages texte ou des
-        appels téléphoniques.
+      instruction: Faites de ce numéro de téléphone le numéro par défaut où vous
+        recevez des messages texte ou des appels téléphoniques.
       label: Numéro de téléphone par défaut
+      one_number_instruction: Vous devez avoir ajouté plus d’un numéro de téléphone
+        pour pouvoir sélectionner un numéro de téléphone par défaut.
+      one_number_title: Il s’agit de votre numéro par défaut
       title: Faites-en votre numéro de téléphone par défaut?
     personal_key_fallback:
       question: Vous n’avez pas votre clé personnelle?
diff --git a/spec/features/phone/default_phone_selection_spec.rb b/spec/features/phone/default_phone_selection_spec.rb
index 575317f9b13..0061da6534a 100644
--- a/spec/features/phone/default_phone_selection_spec.rb
+++ b/spec/features/phone/default_phone_selection_spec.rb
@@ -20,6 +20,11 @@
           expiration: TwoFactorAuthenticatable::DIRECT_OTP_VALID_FOR_MINUTES,
         )
       end
+
+      it 'does not indicate that it is the default number on the account page ' do
+        sign_in_before_2fa(user)
+        expect(page).not_to have_content t('account.index.default')
+      end
     end
 
     context 'when the user creates a new default phone number' do
diff --git a/spec/features/phone/edit_phone_spec.rb b/spec/features/phone/edit_phone_spec.rb
index 80e30d9cd26..d5fdc9ec499 100644
--- a/spec/features/phone/edit_phone_spec.rb
+++ b/spec/features/phone/edit_phone_spec.rb
@@ -20,4 +20,18 @@
 
     expect(page).to have_content('The page you were looking for doesn’t exist')
   end
+
+  context 'with only one phone number' do
+    it 'does not allow you to check default phone number if only one number is set up' do
+      user = create(:user, :signed_up)
+      phone_configuration = user.phone_configurations.first
+      sign_in_and_2fa_user(user)
+
+      visit(manage_phone_path(id: phone_configuration.id))
+      expect(page).to have_field(
+        t('two_factor_authentication.otp_make_default_number.label'),
+        disabled: true,
+      )
+    end
+  end
 end
diff --git a/spec/forms/edit_phone_form_spec.rb b/spec/forms/edit_phone_form_spec.rb
index 156d94eec04..6cf09f75093 100644
--- a/spec/forms/edit_phone_form_spec.rb
+++ b/spec/forms/edit_phone_form_spec.rb
@@ -11,7 +11,7 @@
     }
   end
 
-  subject { described_class.new(user, phone_configuration) }
+  subject { EditPhoneForm.new(user, phone_configuration) }
 
   describe '#submit' do
     context 'when delivery_preference is not voice or sms' do
@@ -107,4 +107,25 @@
       end
     end
   end
+
+  describe '#one_phone_configured?' do
+    context 'when editing a form with only one number set up' do
+      let(:user) { create(:user, :signed_up) }
+      let(:phone_configuration) { user.phone_configurations.first }
+
+      it 'recognizes it as the only method set up' do
+        expect(subject.one_phone_configured?).to eq(true)
+      end
+    end
+
+    context 'when editing a form with multiple numbers set up' do
+      before do
+        create(:phone_configuration, user: user, made_default_at: Time.zone.now)
+      end
+
+      it 'recognizes that there are multiple phone methods set up' do
+        expect(user.phone_configurations.count).to eq(2)
+      end
+    end
+  end
 end