diff --git a/beesdoo_website_shift/controllers/main.py b/beesdoo_website_shift/controllers/main.py
index cdb502e..a3f4e92 100644
--- a/beesdoo_website_shift/controllers/main.py
+++ b/beesdoo_website_shift/controllers/main.py
@@ -135,6 +135,7 @@ class WebsiteShiftController(http.Controller):
             * the given shift exist
             * the shift status is open
             * the shift is free for subscription
+            * the shift is starting in more than 20 minutes
         """
         # Get current user
         cur_user = request.env['res.users'].browse(request.uid)
@@ -143,12 +144,16 @@ class WebsiteShiftController(http.Controller):
         # Get config
         irregular_enable_sign_up = literal_eval(request.env['ir.config_parameter'].get_param(
             'beesdoo_website_shift.irregular_enable_sign_up'))
-
+        # Set start time limit
+        start_time_limit = datetime.now() + timedelta(minutes = 20)
+        shift_start_time = fields.Datetime.from_string(shift.start_time)
         request.session['success'] = False
+
         if (irregular_enable_sign_up
                 and self.user_can_subscribe()
                 and shift
                 and shift.state == "open"
+                and shift_start_time > start_time_limit
                 and not shift.worker_id):
             shift.worker_id = cur_user.partner_id
             request.session['success'] = True
diff --git a/beesdoo_website_shift/i18n/fr_BE.po b/beesdoo_website_shift/i18n/fr_BE.po
index 34252a0..219d88e 100644
--- a/beesdoo_website_shift/i18n/fr_BE.po
+++ b/beesdoo_website_shift/i18n/fr_BE.po
@@ -167,7 +167,7 @@ msgstr "Appliquer"
 
 #. module: beesdoo_website_shift
 #: model:ir.ui.view,arch_db:beesdoo_website_shift.available_shift_irregular_worker
-msgid "Are you shure you want to subscribe to this shift?"
+msgid "Please confirm subscription"
 msgstr "Etes-vous sûr de vouloir vous inscrire à ce shift ?"
 
 #. module: beesdoo_website_shift
diff --git a/beesdoo_website_shift/views/my_shift_website_templates.xml b/beesdoo_website_shift/views/my_shift_website_templates.xml
index c73d475..56356c1 100644
--- a/beesdoo_website_shift/views/my_shift_website_templates.xml
+++ b/beesdoo_website_shift/views/my_shift_website_templates.xml
@@ -480,7 +480,7 @@
                 <span aria-hidden="true">×</span>
               </button>
               <h4 class="modal-title" t-att-id="'subscribe-shift-%s-label' % shift.id">
-                Are you shure you want to subscribe to this shift?
+                Please confirm subscription
               </h4>
             </div>
             <div class="modal-body">
@@ -901,6 +901,8 @@
                   <strong>Failed!</strong> Your subscription has failed. Someone
                   subscribed before you or the shift was deleted. Try again in a
                   moment.
+
+                  Please note that you can't subscribe 20 minutes before the shift.
                 </t>
               </div>