diff --git a/frontend/dashboard.css b/frontend/dashboard.css
index 8c48178..980ddc6 100644
--- a/frontend/dashboard.css
+++ b/frontend/dashboard.css
@@ -201,6 +201,11 @@ textarea { resize: vertical; min-height: 120px; }
 .plan-today-header { display:flex; align-items:flex-start; justify-content:space-between; gap:12px; }
 .plan-today-header h2, .plan-today-header p { margin-top:0; }
 .plan-today-header button { min-width:44px; min-height:44px; }
+.mobile-plan-today-nav { position:sticky; top:0; z-index:5; display:grid; grid-template-columns:repeat(3,minmax(0,1fr)); gap:4px; margin:0 -18px 10px; padding:4px 18px; background:rgba(11,21,38,.98); border-block:1px solid #2a496e; }
+.mobile-plan-today-nav button { min-width:0; min-height:44px; padding:4px; border-color:transparent; font-size:12px; }
+.mobile-plan-today-nav button[aria-current="location"] { color:#bfdbfe; background:#17365a; border-color:#31577f; }
+#plan-today-fit, #plan-today-selected, #plan-today-available-work { scroll-margin-top:54px; }
+@media (min-width:601px) { .mobile-plan-today-nav { display:none; } }
 .plan-today-list button, .plan-today-candidates button { min-height:44px; }
 .plan-today-capacity { position:sticky; top:0; z-index:2; margin:8px 0; padding:10px 12px; border:1px solid #31577f; border-radius:10px; background:#10233a; font-weight:700; }
 .plan-today-available { display:flex; align-items:center; justify-content:space-between; gap:12px; margin:10px 0; font-weight:700; }
@@ -908,6 +913,8 @@ textarea { resize: vertical; min-height: 120px; }
   .card-planning:not([open]) > .card-planning-actions { display:none; }
   .card-planning[open] > .card-planning-actions { display:grid; margin-top:8px; }
   .plan-today-panel { width:100%; border-left:0; padding:14px; }
+  .mobile-plan-today-nav { margin-inline:-14px; padding-inline:14px; }
+  .plan-today-capacity { position:static; }
   .plan-today-item { grid-template-columns:1fr; }
   .plan-today-item-actions { display:grid; grid-template-columns:repeat(3,1fr); width:100%; }
   .plan-today-candidate-actions { grid-template-columns:repeat(2,1fr); width:100%; }
diff --git a/frontend/index.html b/frontend/index.html
index 6a1ca0c..2bcebe1 100644
--- a/frontend/index.html
+++ b/frontend/index.html
@@ -342,6 +342,12 @@
       <div><h2 id="plan-today-title">Plan Today</h2><p class="small muted">Choose and order the work you want to finish next.</p></div>
       <button id="cancel-plan-today" type="button">Cancel</button>
     </div>
+    <nav class="mobile-plan-today-nav" aria-label="Plan Today sections">
+      <button type="button" data-plan-today-section="fit" aria-current="location">Fit</button>
+      <button type="button" data-plan-today-section="today">Today</button>
+      <button type="button" data-plan-today-section="available">Available</button>
+    </nav>
+    <section id="plan-today-fit" aria-label="Fit today's work">
     <div class="plan-today-capacity" id="plan-today-capacity" role="status" aria-live="polite">0 of 5 selected</div>
     <label class="plan-today-available" for="plan-today-available">Available today
       <span><input id="plan-today-available" type="number" inputmode="numeric" min="15" max="1440" step="15" placeholder="Minutes" /> min</span>
@@ -356,11 +362,12 @@
     <div class="plan-today-skipped" id="plan-today-skipped"></div>
     <div class="small plan-today-error" id="plan-today-error" role="alert"></div>
     <button class="discard-recap-replan" id="discard-recap-replan" type="button" hidden>Discard recap feedback</button>
-    <section aria-labelledby="today-plan-heading">
+    </section>
+    <section id="plan-today-selected" aria-labelledby="today-plan-heading">
       <h3 id="today-plan-heading">Today, in order</h3>
       <div class="plan-today-list" id="plan-today-list"></div>
     </section>
-    <section aria-labelledby="today-candidates-heading">
+    <section id="plan-today-available-work" aria-labelledby="today-candidates-heading">
       <h3 id="today-candidates-heading">Available My Work</h3>
       <div class="plan-today-candidates" id="plan-today-candidates"></div>
     </section>
@@ -1588,6 +1595,7 @@
 <script src="static/mobile-update-detail-nav.js"></script>
 <script src="static/mobile-review-detail-nav.js"></script>
 <script src="static/mobile-search-preview-nav.js"></script>
+<script src="static/mobile-plan-today-nav.js"></script>
 <script src="static/dashboard.js"></script>
 </body>
 </html>
diff --git a/frontend/mobile-plan-today-nav.js b/frontend/mobile-plan-today-nav.js
new file mode 100644
index 0000000..a5f11a0
--- /dev/null
+++ b/frontend/mobile-plan-today-nav.js
@@ -0,0 +1,104 @@
+function createMobilePlanTodayNavigation(options) {
+  const buttons = options.buttons || {};
+  const targets = options.targets || {};
+  const root = options.root;
+  const listeners = new Map();
+  const prefersReducedMotion = options.prefersReducedMotion || (() => false);
+  const now = options.now || (() => Date.now());
+  const targetNames = new Map(Object.entries(targets).map(([name, target]) => [target, name]));
+  let observer = null;
+  let navigationLockUntil = 0;
+
+  function select(name) {
+    Object.entries(buttons).forEach(([key, button]) => {
+      if (!button) return;
+      if (key === name) button.setAttribute('aria-current', 'location');
+      else button.removeAttribute('aria-current');
+    });
+  }
+
+  function navigate(name) {
+    const target = targets[name];
+    if (!root || !target) return false;
+    root.scrollTo({
+      top: Math.max(0, target.offsetTop - root.offsetTop),
+      behavior: prefersReducedMotion() ? 'auto' : 'smooth',
+    });
+    navigationLockUntil = now() + 500;
+    select(name);
+    return true;
+  }
+
+  function reset() {
+    select('fit');
+  }
+
+  return {
+    start() {
+      Object.entries(buttons).forEach(([name, button]) => {
+        if (!button || listeners.has(button)) return;
+        const listener = event => {
+          event.preventDefault();
+          navigate(name);
+        };
+        listeners.set(button, listener);
+        button.addEventListener('click', listener);
+      });
+      reset();
+      const observe = options.observe || ((handler, observedTargets, observedRoot) => {
+        if (typeof IntersectionObserver === 'undefined') return null;
+        const instance = new IntersectionObserver(handler, {
+          root: observedRoot,
+          rootMargin: '-20% 0px -60% 0px',
+          threshold: [0, 0.25, 0.5, 0.75, 1],
+        });
+        observedTargets.forEach(target => instance.observe(target));
+        return instance;
+      });
+      observer = observe(entries => {
+        if (now() < navigationLockUntil) return;
+        const visible = entries
+          .filter(entry => entry.isIntersecting && targetNames.has(entry.target))
+          .sort((left, right) => right.intersectionRatio - left.intersectionRatio)[0];
+        if (visible) select(targetNames.get(visible.target));
+      }, Array.from(targetNames.keys()).filter(Boolean), root);
+    },
+    stop() {
+      listeners.forEach((listener, button) => button.removeEventListener('click', listener));
+      listeners.clear();
+      if (observer) observer.disconnect();
+      observer = null;
+    },
+    navigate,
+    reset,
+    select,
+  };
+}
+
+function attachMobilePlanTodayNavigation({document, window}) {
+  const bySection = name => document.querySelector('[data-plan-today-section="' + name + '"]');
+  const sheet = document.getElementById('plan-today-sheet');
+  const panel = document.querySelector('.plan-today-panel');
+  const navigation = createMobilePlanTodayNavigation({
+    root: panel,
+    buttons: {
+      fit: bySection('fit'),
+      today: bySection('today'),
+      available: bySection('available'),
+    },
+    targets: {
+      fit: document.getElementById('plan-today-fit'),
+      today: document.getElementById('plan-today-selected'),
+      available: document.getElementById('plan-today-available-work'),
+    },
+    prefersReducedMotion: () => window.matchMedia('(prefers-reduced-motion: reduce)').matches,
+  });
+  navigation.start();
+  new MutationObserver(() => {
+    if (!sheet.hidden) navigation.reset();
+  }).observe(sheet, {attributes: true, attributeFilter: ['hidden']});
+  return navigation;
+}
+
+if (typeof module !== 'undefined') module.exports = createMobilePlanTodayNavigation;
+else attachMobilePlanTodayNavigation({document, window});
diff --git a/frontend/service-worker.js b/frontend/service-worker.js
index e5ba95b..3b5a917 100644
--- a/frontend/service-worker.js
+++ b/frontend/service-worker.js
@@ -81,6 +81,7 @@ const SHELL = [
   BASE + 'static/mobile-update-detail-nav.js',
   BASE + 'static/mobile-review-detail-nav.js',
   BASE + 'static/mobile-search-preview-nav.js',
+  BASE + 'static/mobile-plan-today-nav.js',
   BASE + 'static/checklist-conflict.js',
   BASE + 'static/voice-transcript-store.js',
   BASE + 'static/voice-issue-capture.js',
diff --git a/src/frontend_bundle.py b/src/frontend_bundle.py
index 7445bc1..fde9756 100644
--- a/src/frontend_bundle.py
+++ b/src/frontend_bundle.py
@@ -30,7 +30,7 @@ FEATURE_SOURCES = {
     "device-setup": ("static/install-app.js", "static/mobile-device-setup.js"),
     "security-center": ("static/security-center.js",),
     "today-timer": (
-        "static/voice-transcript-store.js", "static/voice-conversation-capture.js",
+        "static/voice-transcript-store.js", "static/voice-conversation-capture.js", "static/mobile-plan-today-nav.js",
         "static/today-completion.js", "static/work-detail-position.js", "static/work-route.js", "static/commands.js", "static/saved-searches.js", "static/task-overlay-history.js", "static/search-preview.js", "static/mobile-search-preview-nav.js", "static/search-reply-draft-store.js", "static/conversation-reply-draft-store.js", "static/conversation-photo-drafts.js", "static/search-defer.js", "static/mobile-search-viewport.js", "static/my-work.js", "static/protect-today.js", "static/mobile-task-dock.js", "static/mobile-queue-launcher.js", "static/mobile-start-day.js", "static/update-triage-session.js", "static/update-review-handoff.js", "static/update-triage-launcher.js", "static/update-triage-gesture.js", "static/notification-undo.js", "static/today-timer.js", "static/today-recap.js",
         "static/today-rollover.js", "static/later-work.js", "static/later-picker.js", "static/drafts.js", "static/unfiled-captures.js", "static/unfiled-draft-sync.js",
         "static/assign-and-start.js", "static/filed-claim.js", "static/queue-today.js", "static/create-and-start.js",
diff --git a/tests/test_mobile_plan_today_navigation.py b/tests/test_mobile_plan_today_navigation.py
new file mode 100644
index 0000000..b44567e
--- /dev/null
+++ b/tests/test_mobile_plan_today_navigation.py
@@ -0,0 +1,103 @@
+import json
+import subprocess
+from pathlib import Path
+
+
+CONTROLLER = Path(__file__).resolve().parents[1] / "frontend" / "mobile-plan-today-nav.js"
+FRONTEND = CONTROLLER.parent
+
+
+def run_navigation(scenario: str) -> dict:
+    script = f"""
+const createNavigation = require({json.dumps(str(CONTROLLER))});
+class FakeElement {{
+  constructor(name, offsetTop=0) {{
+    this.name=name; this.offsetTop=offsetTop; this.listeners={{}}; this.attributes={{}};
+    this.scrolls=[]; this.hidden=false;
+  }}
+  addEventListener(name, callback) {{ this.listeners[name]=callback; }}
+  removeEventListener(name) {{ delete this.listeners[name]; }}
+  click() {{ this.listeners.click?.({{preventDefault() {{}}}}); }}
+  setAttribute(name,value) {{ this.attributes[name]=value; }}
+  removeAttribute(name) {{ delete this.attributes[name]; }}
+  scrollTo(options) {{ this.scrolls.push(options); }}
+}}
+{scenario}
+"""
+    result = subprocess.run(["node", "-e", script], capture_output=True, text=True)
+    assert result.returncode == 0, result.stderr
+    return json.loads(result.stdout)
+
+
+def test_mobile_plan_today_navigation_scrolls_the_planner_and_tracks_sections():
+    result = run_navigation("""
+const names=['fit','today','available'];
+const buttons=Object.fromEntries(names.map(name=>[name,new FakeElement(name)]));
+const targets={fit:new FakeElement('fit',120),today:new FakeElement('today',620),available:new FakeElement('available',1120)};
+const root=new FakeElement('panel',100);
+let callback; let observedRoot; let disconnected=0; let now=1000;
+const navigation=createNavigation({
+  buttons,targets,root,prefersReducedMotion:()=>true,now:()=>now,
+  observe(handler,observed,rootOption){callback=handler; observedRoot=rootOption; return {disconnect(){disconnected++;}};},
+});
+navigation.start();
+buttons.today.click();
+now=1600;
+callback([{target:targets.today,isIntersecting:true,intersectionRatio:.2},{target:targets.available,isIntersecting:true,intersectionRatio:.8}]);
+const selected=Object.fromEntries(Object.entries(buttons).map(([name,button])=>[name,button.attributes['aria-current']||null]));
+navigation.stop();
+process.stdout.write(JSON.stringify({scrolls:root.scrolls,selected,observedRoot:observedRoot.name,disconnected,listeners:Object.values(buttons).map(button=>Object.keys(button.listeners).length)}));
+""")
+
+    assert result == {
+        "scrolls": [{"top": 520, "behavior": "auto"}],
+        "selected": {"fit": None, "today": None, "available": "location"},
+        "observedRoot": "panel",
+        "disconnected": 1,
+        "listeners": [0, 0, 0],
+    }
+
+
+def test_mobile_plan_today_navigation_preserves_selection_until_a_fresh_open():
+    result = run_navigation("""
+const names=['fit','today','available'];
+const buttons=Object.fromEntries(names.map(name=>[name,new FakeElement(name)]));
+const targets=Object.fromEntries(names.map((name,index)=>[name,new FakeElement(name,index*400)]));
+const root=new FakeElement('panel');
+const navigation=createNavigation({buttons,targets,root,prefersReducedMotion:()=>false,observe:()=>null});
+navigation.start();
+buttons.available.click();
+const afterRerender=Object.fromEntries(Object.entries(buttons).map(([name,button])=>[name,button.attributes['aria-current']||null]));
+navigation.reset();
+const afterOpen=Object.fromEntries(Object.entries(buttons).map(([name,button])=>[name,button.attributes['aria-current']||null]));
+process.stdout.write(JSON.stringify({scrolls:root.scrolls,afterRerender,afterOpen}));
+""")
+
+    assert result == {
+        "scrolls": [{"top": 800, "behavior": "smooth"}],
+        "afterRerender": {"fit": None, "today": None, "available": "location"},
+        "afterOpen": {"fit": "location", "today": None, "available": None},
+    }
+
+
+def test_plan_today_ships_mobile_navigation_in_the_offline_bundle():
+    html = (FRONTEND / "index.html").read_text()
+    css = (FRONTEND / "dashboard.css").read_text()
+    bundle = (FRONTEND.parent / "src" / "frontend_bundle.py").read_text()
+    service_worker = (FRONTEND / "service-worker.js").read_text()
+
+    assert '<nav class="mobile-plan-today-nav"' in html
+    assert 'aria-label="Plan Today sections"' in html
+    for name, label in (("fit", "Fit"), ("today", "Today"), ("available", "Available")):
+        assert f'data-plan-today-section="{name}"' in html
+        assert f">{label}</button>" in html
+    assert 'id="plan-today-fit"' in html
+    assert 'id="plan-today-selected"' in html
+    assert 'id="plan-today-available-work"' in html
+    assert '<script src="static/mobile-plan-today-nav.js"></script>' in html
+    assert '"static/mobile-plan-today-nav.js"' in bundle
+    assert "static/mobile-plan-today-nav.js" in service_worker
+    assert ".mobile-plan-today-nav" in css
+    assert "grid-template-columns:repeat(3,minmax(0,1fr))" in css
+    assert "min-height:44px" in css
+    assert "@media (min-width:601px)" in css
diff --git a/tests/test_service_worker.py b/tests/test_service_worker.py
index 8b17d36..3f64a53 100644
--- a/tests/test_service_worker.py
+++ b/tests/test_service_worker.py
@@ -1002,6 +1002,7 @@ def test_install_precaches_complete_subpath_scoped_app_shell():
         "/dashboard/static/mobile-update-detail-nav.js",
         "/dashboard/static/mobile-review-detail-nav.js",
         "/dashboard/static/mobile-search-preview-nav.js",
+        "/dashboard/static/mobile-plan-today-nav.js",
         "/dashboard/static/checklist-conflict.js",
         "/dashboard/static/voice-transcript-store.js",
         "/dashboard/static/voice-issue-capture.js",