diff --git a/app/javascript/submission_form/form.vue b/app/javascript/submission_form/form.vue
index 61ae047c..3fbcd4d3 100644
--- a/app/javascript/submission_form/form.vue
+++ b/app/javascript/submission_form/form.vue
@@ -141,11 +141,23 @@
   <form
     v-if="!isCompleted && !isInvite"
     id="complete_form"
+    ref="completeForm"
     class="hidden"
     :action="submitPath"
     method="post"
     @submit.prevent="submitStep"
-  />
+  >
+    <input
+      type="hidden"
+      name="authenticity_token"
+      :value="authenticityToken"
+    >
+    <input
+      value="put"
+      name="_method"
+      type="hidden"
+    >
+  </form>
   <button
     v-if="!isFormVisible && currentField"
     id="expand_form_button"
@@ -1114,7 +1126,8 @@ export default {
       })
     },
     showCompleteButton () {
-      return this.completeButtonContainer && !this.isCompleted && !this.isInvite && this.isFormStarted &&
+      return this.completeButtonContainer && !this.isCompleted && !this.isInvite &&
+        (this.isFormStarted || this.stepFields.length === 0) &&
         !this.stepFields.find((fields) => fields.some((f) => f.required && isEmpty(this.submittedValues[f.uuid])))
     },
     submitButtonText () {
@@ -1614,7 +1627,7 @@ export default {
       }
 
       const currentFieldUuids = this.currentStepFields.map((f) => f.uuid)
-      const currentFieldType = this.currentField.type
+      const currentFieldType = this.currentField?.type
 
       if (!formData && !this.$refs.form.checkValidity() && currentFieldUuids.every((fieldUuid) => isEmpty(this.submittedValues[fieldUuid]) || !isEmpty(this.values[fieldUuid]))) {
         return
@@ -1667,7 +1680,7 @@ export default {
 
       const submitStepIndex = this.currentStep
 
-      const stepPromise = ['signature', 'phone', 'initials', 'payment', 'verification', 'kba'].includes(this.currentField.type)
+      const stepPromise = ['signature', 'phone', 'initials', 'payment', 'verification', 'kba'].includes(this.currentField?.type)
         ? this.$refs.currentStep.submit
         : () => Promise.resolve({})
 
@@ -1682,7 +1695,7 @@ export default {
           })
         })
 
-        const formData = new FormData(this.$refs.form)
+        const formData = new FormData(this.$refs.form || this.$refs.completeForm)
         const isLastStep = (this.onlyRequiredFields ? !this.findNextStep(submitStepIndex) : (submitStepIndex === this.stepFields.length - 1)) || forceComplete
 
         if (isLastStep && !emptyRequiredField && !this.inviteSubmitters.length && !this.optionalInviteSubmitters.length) {
diff --git a/app/views/submit_form/show.html.erb b/app/views/submit_form/show.html.erb
index 48580c8f..7d4f76e1 100644
--- a/app/views/submit_form/show.html.erb
+++ b/app/views/submit_form/show.html.erb
@@ -33,7 +33,9 @@
                 </button>
               </modal-button>
             <% end %>
-            <span id="complete_button_container" class="peer contents"></span>
+            <% unless @submitter.viewer? %>
+              <span id="complete_button_container" class="peer contents"></span>
+            <% end %>
             <% if @form_configs[:with_delegate] && !@submitter.viewer? %>
               <modal-button data-target="<%= delegate_modal_id = SecureRandom.uuid %>" class="hidden peer-empty:flex">
                 <button id="delegate_button" type="button" class="btn btn-sm !px-5"><%= t(:delegate) %></button>
@@ -84,7 +86,9 @@
               </button>
             </modal-button>
           <% end %>
-          <span id="complete_button_container_scroll" class="peer contents"></span>
+          <% unless @submitter.viewer? %>
+            <span id="complete_button_container_scroll" class="peer contents"></span>
+          <% end %>
           <% if @form_configs[:with_delegate] && !@submitter.viewer? %>
             <modal-button data-target="<%= delegate_modal_id %>" class="hidden peer-empty:flex">
               <button id="delegate_button_mobile" type="button" class="btn btn-sm px-0" aria-label="<%= t(:delegate) %>">
diff --git a/spec/system/signing_form_spec.rb b/spec/system/signing_form_spec.rb
index d4c2dc43..d92489ff 100644
--- a/spec/system/signing_form_spec.rb
+++ b/spec/system/signing_form_spec.rb
@@ -1317,6 +1317,29 @@ RSpec.describe 'Signing Form' do
       expect(submitter.completed_at).to be_present
       expect(field_value(submitter, 'First Name')).to eq 'John Doe'
     end
+
+    it 'completes a form containing only readonly fields' do
+      template.fields.each do |field|
+        field['readonly'] = true
+        field['default_value'] = "Default #{field['name']}"
+      end
+      template.save!
+      submission.update!(template_fields: template.fields)
+
+      visit submit_form_path(slug: submitter.slug)
+
+      expect(page).to have_css('#complete_button_container button')
+
+      find('#complete_button_container button').click
+
+      expect(page).to have_content('Form has been completed!')
+
+      submitter.reload
+
+      expect(submitter.completed_at).to be_present
+      expect(field_value(submitter, 'First Name')).to eq 'Default First Name'
+      expect(field_value(submitter, 'Birthday')).to eq 'Default Birthday'
+    end
   end
 
   context 'when a view-only party opens the form' do
@@ -1339,6 +1362,7 @@ RSpec.describe 'Signing Form' do
 
       expect(page).to have_content(template.name)
       expect(page).to have_no_css('#form_container')
+      expect(page).to have_no_css('#complete_button_container')
     end
   end
 end