diff --git a/application/views/station_profile/edit.php b/application/views/station_profile/edit.php
index 94c2a4eab..25fa3b41e 100644
--- a/application/views/station_profile/edit.php
+++ b/application/views/station_profile/edit.php
@@ -71,7 +71,7 @@ if ($dxcc_list->result() > 0) {
 
 					<div class="mb-3">
 						<label for="stationCallsignInput"><?= __("Station Callsign"); ?></label>
-						<input type="text" class="form-control uppercase" name="station_callsign" id="stationCallsignInput" aria-describedby="stationCallsignInputHelp" value="<?php if(set_value('station_callsign') != "") { echo set_value('station_callsign'); } else { echo $my_station_profile->station_callsign; } ?>" required>
+						<input type="text" class="form-control uppercase" pattern="^\S+$" name="station_callsign" id="stationCallsignInput" aria-describedby="stationCallsignInputHelp" value="<?php if(set_value('station_callsign') != "") { echo set_value('station_callsign'); } else { echo $my_station_profile->station_callsign; } ?>" required>
 						<small id="stationCallsignInputHelp" class="form-text text-muted"><?= __("Station callsign. For example: 4W7EST/P"); ?></small>
 					</div>
 
diff --git a/application/views/user/edit.php b/application/views/user/edit.php
index 5fdb0307c..7801350fb 100644
--- a/application/views/user/edit.php
+++ b/application/views/user/edit.php
@@ -136,7 +136,7 @@
 								<div class="card-body">
 									<div class="mb-3">
 										<label><?php if ($clubstation) { echo __("Special/Club Callsign"); } else { echo __("Callsign"); } ?></label>
-										<input class="form-control uppercase" type="text" name="user_callsign" value="<?php if(isset($user_callsign)) { echo $user_callsign; } ?>" />
+										<input class="form-control uppercase" type="text" name="user_callsign" pattern="^\S+$" value="<?php if(isset($user_callsign)) { echo $user_callsign; } ?>" />
 											<?php if(isset($callsign_error)) { echo "<small class=\"badge bg-danger\">".$callsign_error."</small>"; } else { ?>
 											<?php } ?>
 									</div>
diff --git a/application/views/user/modals/first_login_wizard.php b/application/views/user/modals/first_login_wizard.php
index 68f312328..f067373cf 100644
--- a/application/views/user/modals/first_login_wizard.php
+++ b/application/views/user/modals/first_login_wizard.php
@@ -34,7 +34,7 @@
                                         <label for="station_callsign" class="form-label mb-0"><?= __("Station Callsign"); ?></label>
                                     </div>
                                     <div class="col-md-8">
-                                        <input type="text" class="form-control uppercase" id="station_callsign" name="station_callsign" placeholder="4W7EST" required>
+                                        <input type="text" class="form-control uppercase" id="station_callsign" pattern="^\S+$" name="station_callsign" placeholder="4W7EST" required>
                                     </div>
                                 </div>
                                 <div class="row mb-3 align-items-center">