diff --git a/p2p/net/connmgr/connmgr.go b/p2p/net/connmgr/connmgr.go
index c3587ad4e3..3a1acf0db0 100644
--- a/p2p/net/connmgr/connmgr.go
+++ b/p2p/net/connmgr/connmgr.go
@@ -7,6 +7,7 @@ import (
 	"sync/atomic"
 	"time"
 
+	"github.com/benbjohnson/clock"
 	"github.com/libp2p/go-libp2p/core/connmgr"
 	"github.com/libp2p/go-libp2p/core/network"
 	"github.com/libp2p/go-libp2p/core/peer"
@@ -27,6 +28,8 @@ var log = logging.Logger("connmgr")
 type BasicConnMgr struct {
 	*decayer
 
+	clock clock.Clock
+
 	cfg      *config
 	segments segments
 
@@ -74,7 +77,7 @@ func (ss *segments) countPeers() (count int) {
 	return count
 }
 
-func (s *segment) tagInfoFor(p peer.ID) *peerInfo {
+func (s *segment) tagInfoFor(p peer.ID, now time.Time) *peerInfo {
 	pi, ok := s.peers[p]
 	if ok {
 		return pi
@@ -82,7 +85,7 @@ func (s *segment) tagInfoFor(p peer.ID) *peerInfo {
 	// create a temporary peer to buffer early tags before the Connected notification arrives.
 	pi = &peerInfo{
 		id:        p,
-		firstSeen: time.Now(), // this timestamp will be updated when the first Connected notification arrives.
+		firstSeen: now, // this timestamp will be updated when the first Connected notification arrives.
 		temp:      true,
 		tags:      make(map[string]int),
 		decaying:  make(map[*decayingTag]*connmgr.DecayingValue),
@@ -102,6 +105,7 @@ func NewConnManager(low, hi int, opts ...Option) (*BasicConnMgr, error) {
 		lowWater:      low,
 		gracePeriod:   time.Minute,
 		silencePeriod: 10 * time.Second,
+		clock:         clock.New(),
 	}
 	for _, o := range opts {
 		if err := o(cfg); err != nil {
@@ -116,6 +120,7 @@ func NewConnManager(low, hi int, opts ...Option) (*BasicConnMgr, error) {
 
 	cm := &BasicConnMgr{
 		cfg:       cfg,
+		clock:     cfg.clock,
 		protected: make(map[peer.ID]map[string]struct{}, 16),
 		segments: func() (ret segments) {
 			for i := range ret {
@@ -167,7 +172,7 @@ func (cm *BasicConnMgr) memoryEmergency() {
 
 	// finally, update the last trim time.
 	cm.lastTrimMu.Lock()
-	cm.lastTrim = time.Now()
+	cm.lastTrim = cm.clock.Now()
 	cm.lastTrimMu.Unlock()
 }
 
@@ -311,7 +316,7 @@ func (cm *BasicConnMgr) background() {
 		interval = cm.cfg.silencePeriod
 	}
 
-	ticker := time.NewTicker(interval)
+	ticker := cm.clock.Ticker(interval)
 	defer ticker.Stop()
 
 	for {
@@ -336,7 +341,7 @@ func (cm *BasicConnMgr) doTrim() {
 	if count == atomic.LoadUint64(&cm.trimCount) {
 		cm.trim()
 		cm.lastTrimMu.Lock()
-		cm.lastTrim = time.Now()
+		cm.lastTrim = cm.clock.Now()
 		cm.lastTrimMu.Unlock()
 		atomic.AddUint64(&cm.trimCount, 1)
 	}
@@ -427,7 +432,7 @@ func (cm *BasicConnMgr) getConnsToClose() []network.Conn {
 
 	candidates := make(peerInfos, 0, cm.segments.countPeers())
 	var ncandidates int
-	gracePeriodStart := time.Now().Add(-cm.cfg.gracePeriod)
+	gracePeriodStart := cm.clock.Now().Add(-cm.cfg.gracePeriod)
 
 	cm.plk.RLock()
 	for _, s := range cm.segments {
@@ -529,7 +534,7 @@ func (cm *BasicConnMgr) TagPeer(p peer.ID, tag string, val int) {
 	s.Lock()
 	defer s.Unlock()
 
-	pi := s.tagInfoFor(p)
+	pi := s.tagInfoFor(p, cm.clock.Now())
 
 	// Update the total value of the peer.
 	pi.value += val - pi.tags[tag]
@@ -559,7 +564,7 @@ func (cm *BasicConnMgr) UpsertTag(p peer.ID, tag string, upsert func(int) int) {
 	s.Lock()
 	defer s.Unlock()
 
-	pi := s.tagInfoFor(p)
+	pi := s.tagInfoFor(p, cm.clock.Now())
 
 	oldval := pi.tags[tag]
 	newval := upsert(oldval)
@@ -629,7 +634,7 @@ func (nn *cmNotifee) Connected(n network.Network, c network.Conn) {
 	if !ok {
 		pinfo = &peerInfo{
 			id:        id,
-			firstSeen: time.Now(),
+			firstSeen: cm.clock.Now(),
 			tags:      make(map[string]int),
 			decaying:  make(map[*decayingTag]*connmgr.DecayingValue),
 			conns:     make(map[network.Conn]time.Time),
@@ -640,7 +645,7 @@ func (nn *cmNotifee) Connected(n network.Network, c network.Conn) {
 		// Connected notification arrived: flip the temporary flag, and update the firstSeen
 		// timestamp to the real one.
 		pinfo.temp = false
-		pinfo.firstSeen = time.Now()
+		pinfo.firstSeen = cm.clock.Now()
 	}
 
 	_, ok = pinfo.conns[c]
@@ -649,7 +654,7 @@ func (nn *cmNotifee) Connected(n network.Network, c network.Conn) {
 		return
 	}
 
-	pinfo.conns[c] = time.Now()
+	pinfo.conns[c] = cm.clock.Now()
 	atomic.AddInt32(&cm.connCount, 1)
 }
 
diff --git a/p2p/net/connmgr/connmgr_test.go b/p2p/net/connmgr/connmgr_test.go
index 92c273c5f0..312bdc1f3b 100644
--- a/p2p/net/connmgr/connmgr_test.go
+++ b/p2p/net/connmgr/connmgr_test.go
@@ -7,6 +7,7 @@ import (
 	"testing"
 	"time"
 
+	"github.com/benbjohnson/clock"
 	"github.com/libp2p/go-libp2p/core/crypto"
 	"github.com/libp2p/go-libp2p/core/network"
 	"github.com/libp2p/go-libp2p/core/peer"
@@ -411,7 +412,8 @@ func TestDisconnected(t *testing.T) {
 
 func TestGracePeriod(t *testing.T) {
 	const gp = 100 * time.Millisecond
-	cm, err := NewConnManager(10, 20, WithGracePeriod(gp), WithSilencePeriod(time.Hour))
+	mockClock := clock.NewMock()
+	cm, err := NewConnManager(10, 20, WithGracePeriod(gp), WithSilencePeriod(time.Hour), WithClock(mockClock))
 	require.NoError(t, err)
 	defer cm.Close()
 
@@ -425,7 +427,7 @@ func TestGracePeriod(t *testing.T) {
 		conns = append(conns, rc)
 		not.Connected(nil, rc)
 
-		time.Sleep(2 * gp)
+		mockClock.Add(2 * gp)
 
 		if rc.(*tconn).isClosed() {
 			t.Fatal("expected conn to remain open")
@@ -447,7 +449,7 @@ func TestGracePeriod(t *testing.T) {
 		}
 	}
 
-	time.Sleep(200 * time.Millisecond)
+	mockClock.Add(200 * time.Millisecond)
 
 	cm.TrimOpenConns(context.Background())
 
@@ -465,7 +467,8 @@ func TestGracePeriod(t *testing.T) {
 
 // see https://github.com/libp2p/go-libp2p-connmgr/issues/23
 func TestQuickBurstRespectsSilencePeriod(t *testing.T) {
-	cm, err := NewConnManager(10, 20, WithGracePeriod(0))
+	mockClock := clock.NewMock()
+	cm, err := NewConnManager(10, 20, WithGracePeriod(0), WithClock(mockClock))
 	require.NoError(t, err)
 	defer cm.Close()
 	not := cm.Notifee()
@@ -480,7 +483,7 @@ func TestQuickBurstRespectsSilencePeriod(t *testing.T) {
 	}
 
 	// wait for a few seconds
-	time.Sleep(time.Second * 3)
+	mockClock.Add(3 * time.Second)
 
 	// only the first trim is allowed in; make sure we close at most 20 connections, not all of them.
 	var closed int
diff --git a/p2p/net/connmgr/decay.go b/p2p/net/connmgr/decay.go
index 9841c2f1fa..0819bd2136 100644
--- a/p2p/net/connmgr/decay.go
+++ b/p2p/net/connmgr/decay.go
@@ -221,7 +221,7 @@ func (d *decayer) process() {
 			s := d.mgr.segments.get(peer)
 			s.Lock()
 
-			p := s.tagInfoFor(peer)
+			p := s.tagInfoFor(peer, d.clock.Now())
 			v, ok := p.decaying[tag]
 			if !ok {
 				v = &connmgr.DecayingValue{
@@ -244,7 +244,7 @@ func (d *decayer) process() {
 			s := d.mgr.segments.get(rm.peer)
 			s.Lock()
 
-			p := s.tagInfoFor(rm.peer)
+			p := s.tagInfoFor(rm.peer, d.clock.Now())
 			v, ok := p.decaying[rm.tag]
 			if !ok {
 				s.Unlock()
diff --git a/p2p/net/connmgr/options.go b/p2p/net/connmgr/options.go
index 76b4ef386d..cde1fd792a 100644
--- a/p2p/net/connmgr/options.go
+++ b/p2p/net/connmgr/options.go
@@ -3,6 +3,8 @@ package connmgr
 import (
 	"errors"
 	"time"
+
+	"github.com/benbjohnson/clock"
 )
 
 // config is the configuration struct for the basic connection manager.
@@ -13,6 +15,7 @@ type config struct {
 	silencePeriod time.Duration
 	decayer       *DecayerCfg
 	emergencyTrim bool
+	clock         clock.Clock
 }
 
 // Option represents an option for the basic connection manager.
@@ -26,6 +29,14 @@ func DecayerConfig(opts *DecayerCfg) Option {
 	}
 }
 
+// WithClock sets the internal clock impl
+func WithClock(c clock.Clock) Option {
+	return func(cfg *config) error {
+		cfg.clock = c
+		return nil
+	}
+}
+
 // WithGracePeriod sets the grace period.
 // The grace period is the time a newly opened connection is given before it becomes
 // subject to pruning.