diff --git a/src/static/riot/competitions/detail/_tabs.tag b/src/static/riot/competitions/detail/_tabs.tag
index 15a8246b3..719308664 100644
--- a/src/static/riot/competitions/detail/_tabs.tag
+++ b/src/static/riot/competitions/detail/_tabs.tag
@@ -280,6 +280,40 @@
                 })
             })
 
+            // loop over competition phases to mark if phase has started or ended
+            self.competition.phases.forEach(function (phase, index) {
+                
+                phase_ended = false 
+                phase_started = false
+
+                // check if phase has started
+                if((Date.parse(phase["start"]) - Date.parse(new Date())) > 0){
+                    // start date is in the future, phase started = NO
+                    phase_started = false
+                }else{
+                    // start date is not in the future, phase started = YES
+                    phase_started = true
+                }
+
+                if(phase_started){
+                    // check if end data exists for this phase
+                    if(phase["end"]){
+                        if((Date.parse(phase["end"]) - Date.parse(new Date())) < 0){
+                            // Phase cannote accept submissions if end date is in the past
+                            phase_ended = true
+                        }else{
+                            // Phase can accept submissions if end date is in the future
+                            phase_ended = false
+                        }
+                    }else{
+                        // Phase can accept submissions if end date is not given
+                        phase_ended = false
+                    }
+                }
+                self.competition.phases[index]["phase_ended"] = phase_ended
+                self.competition.phases[index]["phase_started"] = phase_started
+            })
+
             self.competition.is_admin = CODALAB.state.user.has_competition_admin_privileges(competition)
             self.selected_phase_index = _.get(_.find(self.competition.phases, {'status': 'Current'}), 'id')
             if (self.selected_phase_index == null) {
diff --git a/src/static/riot/competitions/detail/submission_upload.tag b/src/static/riot/competitions/detail/submission_upload.tag
index 4172bd78a..f1405cfb9 100644
--- a/src/static/riot/competitions/detail/submission_upload.tag
+++ b/src/static/riot/competitions/detail/submission_upload.tag
@@ -4,6 +4,8 @@
 
         <div class="submission-form">
             <h1>Submission upload</h1>
+            <div if="{_.get(selected_phase, 'phase_ended')}" class="ui red message">This phase has ended and no longer accepts submissions!</div>
+            <div if="{!_.get(selected_phase, 'phase_started')}" class="ui yellow message">This phase hasn't started yet!</div>
             <form class="ui form coda-animated {error: errors}" ref="form" enctype="multipart/form-data">
                 <div class="submission-form" ref="fact_sheet_form" if="{ opts.fact_sheet !== null}">
                     <h2>Metadata or Fact Sheet</h2>
@@ -349,17 +351,33 @@
         }
 
         self.check_can_upload = function () {
-            CODALAB.api.can_make_submissions(self.selected_phase.id)
-                .done(function (data) {
-                    if (data.can) {
-                        self.prepare_upload(self.upload)()
-                    } else {
-                        toastr.error(data.reason)
+            
+            // Check if selected phase accepts submissions (within the deadline of the phase)
+            if(self.selected_phase.phase_started && !self.selected_phase.phase_ended){
+
+                CODALAB.api.can_make_submissions(self.selected_phase.id)
+                    .done(function (data) {
+                        if (data.can) {
+                            self.prepare_upload(self.upload)()
+                        } else {
+                            toastr.error(data.reason)
+                        }
+                    })
+                    .fail(function (data) {
+                        toastr.error('Could not verify your ability to make a submission')
+                    })
+            }else{
+                // Error when phase is not accepting submissions
+                if(!self.selected_phase.phase_started){
+                    toastr.error('This phase has not started yet. Please check the phase start date!')
+                   
+                }else {
+                    if(self.selected_phase.phase_ended){
+                        toastr.error('This phase has ended and no longer accepts submissions!')
                     }
-                })
-                .fail(function (data) {
-                    toastr.error('Could not verify your ability to make a submission')
-                })
+                }
+                self.clear_form()
+            }
         }
 
         self.get_fact_sheet_answers = function () {
diff --git a/src/tests/functional/test_files/competition.zip b/src/tests/functional/test_files/competition.zip
index ff2121d6a..005fba612 100644
Binary files a/src/tests/functional/test_files/competition.zip and b/src/tests/functional/test_files/competition.zip differ
diff --git a/src/tests/functional/test_files/competition_18.zip b/src/tests/functional/test_files/competition_18.zip
index e0ed2aeef..f5afa821d 100644
Binary files a/src/tests/functional/test_files/competition_18.zip and b/src/tests/functional/test_files/competition_18.zip differ