diff --git a/firefox-ios/firefox-ios-tests/Tests/ClientTests/ShareManagerTests.swift b/firefox-ios/firefox-ios-tests/Tests/ClientTests/ShareManagerTests.swift
index 305520c924ea..59b17b8582d3 100644
--- a/firefox-ios/firefox-ios-tests/Tests/ClientTests/ShareManagerTests.swift
+++ b/firefox-ios/firefox-ios-tests/Tests/ClientTests/ShareManagerTests.swift
@@ -291,8 +291,12 @@ final class ShareManagerTests: XCTestCase {
         _ = try XCTUnwrap(activityItems[safe: 2] as? TabWebView)
 
         let titleActivityItemProvider = try XCTUnwrap(activityItems[safe: 3] as? TitleActivityItemProvider)
+        let itemForTitleActivity = titleActivityItemProvider.activityViewController(
+            createStubActivityViewController(),
+            itemForActivityType: whatsAppActivity
+        )
         XCTAssertEqual(
-            titleActivityItemProvider.item as? String,
+            itemForTitleActivity as? String,
             testWebpageDisplayTitle,
             "When no explicit share message is set, we expect to see the webpage's title."
         )
@@ -332,8 +336,12 @@ final class ShareManagerTests: XCTestCase {
         _ = try XCTUnwrap(activityItems[safe: 2] as? TabWebView)
 
         let titleActivityItemProvider = try XCTUnwrap(activityItems[safe: 3] as? TitleActivityItemProvider)
+        let itemForTitleActivity = titleActivityItemProvider.activityViewController(
+            createStubActivityViewController(),
+            itemForActivityType: whatsAppActivity
+        )
         XCTAssertEqual(
-            titleActivityItemProvider.item as? String,
+            itemForTitleActivity as? String,
             testWebpageDisplayTitle,
             "When no explicit share message is set, we expect to see the webpage's title."
         )
@@ -371,10 +379,13 @@ final class ShareManagerTests: XCTestCase {
         _ = try XCTUnwrap(activityItems[safe: 2] as? TabWebView)
 
         let titleActivityItemProvider = try XCTUnwrap(activityItems[safe: 3] as? TitleActivityItemProvider)
-        XCTAssertEqual(
-            titleActivityItemProvider.item as? String,
-            testWebpageDisplayTitle,
-            "When no explicit share message is set, we expect to see the webpage's title."
+        let itemForTitleActivity = titleActivityItemProvider.activityViewController(
+            createStubActivityViewController(),
+            itemForActivityType: mailActivity
+        )
+        XCTAssertTrue(
+            itemForTitleActivity is NSNull,
+            "When no explicit share message, TitleActivityItemProvider item should not be shared to excluded activity Mail."
         )
     }
 
@@ -411,8 +422,12 @@ final class ShareManagerTests: XCTestCase {
         _ = try XCTUnwrap(activityItems[safe: 2] as? TabWebView)
 
         let titleActivityItemProvider = try XCTUnwrap(activityItems[safe: 3] as? TitleActivityItemProvider)
+        let itemForTitleActivity = titleActivityItemProvider.activityViewController(
+            createStubActivityViewController(),
+            itemForActivityType: whatsAppActivity
+        )
         XCTAssertEqual(
-            titleActivityItemProvider.item as? String,
+            itemForTitleActivity as? String,
             testWebpageDisplayTitle,
             "When no explicit share message is set, we expect to see the webpage's title."
         )
diff --git a/firefox-ios/firefox-ios-tests/Tests/ClientTests/URLActivityItemProviderTests.swift b/firefox-ios/firefox-ios-tests/Tests/ClientTests/URLActivityItemProviderTests.swift
index a62bcde62c66..412495515894 100644
--- a/firefox-ios/firefox-ios-tests/Tests/ClientTests/URLActivityItemProviderTests.swift
+++ b/firefox-ios/firefox-ios-tests/Tests/ClientTests/URLActivityItemProviderTests.swift
@@ -6,8 +6,8 @@ import UniformTypeIdentifiers
 import XCTest
 @testable import Client
 
-// TODO: FXIOS-10816 Flesh out these unit tests
 final class URLActivityItemProviderTests: XCTestCase {
+    let testFileURL = URL(string: "file://some/file/url")!
     let testWebURL = URL(string: "https://mozilla.org")!
 
     override func setUp() {
@@ -16,9 +16,111 @@ final class URLActivityItemProviderTests: XCTestCase {
         LegacyFeatureFlagsManager.shared.initializeDeveloperFeatures(with: MockProfile())
     }
 
+    func testWebURL_forMailActivity() {
+        let testActivityType = UIActivity.ActivityType.mail
+
+        let urlActivityItemProvider = URLActivityItemProvider(url: testWebURL, allowSentFromFirefoxTreatment: false)
+        let urlDataIdentifier = urlActivityItemProvider.activityViewController(
+            createStubActivityViewController(),
+            dataTypeIdentifierForActivityType: testActivityType
+        )
+        let itemForActivity = urlActivityItemProvider.activityViewController(
+            createStubActivityViewController(),
+            itemForActivityType: testActivityType
+        )
+
+        XCTAssertEqual(urlDataIdentifier, UTType.url.identifier)
+        XCTAssertEqual(itemForActivity as? URL, testWebURL)
+    }
+
+    func testWebURL_forMessagesActivity() {
+        let testActivityType = UIActivity.ActivityType.message
+
+        let urlActivityItemProvider = URLActivityItemProvider(url: testWebURL, allowSentFromFirefoxTreatment: false)
+        let urlDataIdentifier = urlActivityItemProvider.activityViewController(
+            createStubActivityViewController(),
+            dataTypeIdentifierForActivityType: testActivityType
+        )
+        let itemForActivity = urlActivityItemProvider.activityViewController(
+            createStubActivityViewController(),
+            itemForActivityType: testActivityType
+        )
+
+        XCTAssertEqual(urlDataIdentifier, UTType.url.identifier)
+        XCTAssertEqual(itemForActivity as? URL, testWebURL)
+    }
+
+    func testFileURL_forMailActivity() {
+        let testActivityType = UIActivity.ActivityType.mail
+
+        let urlActivityItemProvider = URLActivityItemProvider(url: testFileURL, allowSentFromFirefoxTreatment: false)
+        let urlDataIdentifier = urlActivityItemProvider.activityViewController(
+            createStubActivityViewController(),
+            dataTypeIdentifierForActivityType: testActivityType
+        )
+        let itemForActivity = urlActivityItemProvider.activityViewController(
+            createStubActivityViewController(),
+            itemForActivityType: testActivityType
+        )
+
+        XCTAssertEqual(urlDataIdentifier, UTType.fileURL.identifier)
+        XCTAssertEqual(itemForActivity as? URL, testFileURL)
+    }
+
+    func testFileURL_forMessagesActivity() {
+        let testActivityType = UIActivity.ActivityType.message
+
+        let urlActivityItemProvider = URLActivityItemProvider(url: testFileURL, allowSentFromFirefoxTreatment: false)
+        let urlDataIdentifier = urlActivityItemProvider.activityViewController(
+            createStubActivityViewController(),
+            dataTypeIdentifierForActivityType: testActivityType
+        )
+        let itemForActivity = urlActivityItemProvider.activityViewController(
+            createStubActivityViewController(),
+            itemForActivityType: testActivityType
+        )
+
+        XCTAssertEqual(urlDataIdentifier, UTType.fileURL.identifier)
+        XCTAssertEqual(itemForActivity as? URL, testFileURL)
+    }
+
+    func testWebURL_forExcludedActivity() {
+        let testActivityType = UIActivity.ActivityType.addToReadingList
+
+        let urlActivityItemProvider = URLActivityItemProvider(url: testWebURL, allowSentFromFirefoxTreatment: false)
+        let urlDataIdentifier = urlActivityItemProvider.activityViewController(
+            createStubActivityViewController(),
+            dataTypeIdentifierForActivityType: testActivityType
+        )
+        let itemForActivity = urlActivityItemProvider.activityViewController(
+            createStubActivityViewController(),
+            itemForActivityType: testActivityType
+        )
+
+        XCTAssertEqual(urlDataIdentifier, UTType.url.identifier)
+        XCTAssertTrue(itemForActivity is NSNull)
+    }
+
+    func testFileURL_forExcludedActivity() {
+        let testActivityType = UIActivity.ActivityType.addToReadingList
+
+        let urlActivityItemProvider = URLActivityItemProvider(url: testFileURL, allowSentFromFirefoxTreatment: false)
+        let urlDataIdentifier = urlActivityItemProvider.activityViewController(
+            createStubActivityViewController(),
+            dataTypeIdentifierForActivityType: testActivityType
+        )
+        let itemForActivity = urlActivityItemProvider.activityViewController(
+            createStubActivityViewController(),
+            itemForActivityType: testActivityType
+        )
+
+        XCTAssertEqual(urlDataIdentifier, UTType.fileURL.identifier)
+        XCTAssertTrue(itemForActivity is NSNull)
+    }
+
     // MARK: - Sent from Firefox experiment WhatsApp tab share override
 
-    func testOveridesWhatsAppShareItem_forTreatmentA() throws {
+    func testOveridesWhatsAppShareItem_forTreatmentA() {
         setupNimbusSentFromFirefoxTesting(isEnabled: true, isTreatmentA: true)
 
         let expectedShareContentA = "https://mozilla.org Sent from Firefox 🦊 Try the mobile browser: https://mzl.la/4fOWPpd"
@@ -33,7 +135,7 @@ final class URLActivityItemProviderTests: XCTestCase {
         XCTAssertEqual(itemForActivity as? String, expectedShareContentA)
     }
 
-    func testOveridesWhatsAppShareItem_forTreatmentB() throws {
+    func testOveridesWhatsAppShareItem_forTreatmentB() {
         setupNimbusSentFromFirefoxTesting(isEnabled: true, isTreatmentA: false)
 
         let expectedShareContentB = "https://mozilla.org Sent from Firefox 🦊 https://mzl.la/3YSUOl8"