diff --git a/core/network/src/main/java/com/twix/network/UploadHttpClientProvider.kt b/core/network/src/main/java/com/twix/network/UploadHttpClientProvider.kt
new file mode 100644
index 00000000..2c518bf1
--- /dev/null
+++ b/core/network/src/main/java/com/twix/network/UploadHttpClientProvider.kt
@@ -0,0 +1,16 @@
+package com.twix.network
+
+import io.ktor.client.HttpClient
+import io.ktor.client.engine.okhttp.OkHttp
+import io.ktor.client.plugins.HttpTimeout
+
+object UploadHttpClientProvider {
+    fun create(): HttpClient =
+        HttpClient(OkHttp) {
+            install(HttpTimeout) {
+                requestTimeoutMillis = 120_000
+                connectTimeoutMillis = 30_000
+                socketTimeoutMillis = 120_000
+            }
+        }
+}
diff --git a/core/network/src/main/java/com/twix/network/di/ApiServiceModule.kt b/core/network/src/main/java/com/twix/network/di/ApiServiceModule.kt
index 254a0387..fad38938 100644
--- a/core/network/src/main/java/com/twix/network/di/ApiServiceModule.kt
+++ b/core/network/src/main/java/com/twix/network/di/ApiServiceModule.kt
@@ -3,9 +3,11 @@ package com.twix.network.di
 import com.twix.network.service.AuthService
 import com.twix.network.service.GoalService
 import com.twix.network.service.OnboardingService
+import com.twix.network.service.PhotoLogService
 import com.twix.network.service.createAuthService
 import com.twix.network.service.createGoalService
 import com.twix.network.service.createOnboardingService
+import com.twix.network.service.createPhotoLogService
 import de.jensklingenberg.ktorfit.Ktorfit
 import org.koin.dsl.module
 
@@ -20,4 +22,7 @@ internal val apiServiceModule =
         single<GoalService> {
             get<Ktorfit>().createGoalService()
         }
+        single<PhotoLogService> {
+            get<Ktorfit>().createPhotoLogService()
+        }
     }
diff --git a/core/network/src/main/java/com/twix/network/di/HttpClientModule.kt b/core/network/src/main/java/com/twix/network/di/HttpClientModule.kt
index ee8e7417..92463da4 100644
--- a/core/network/src/main/java/com/twix/network/di/HttpClientModule.kt
+++ b/core/network/src/main/java/com/twix/network/di/HttpClientModule.kt
@@ -2,8 +2,11 @@ package com.twix.network.di
 
 import com.twix.network.BuildConfig
 import com.twix.network.HttpClientProvider
+import com.twix.network.UploadHttpClientProvider
+import com.twix.network.upload.PresignedUploader
 import de.jensklingenberg.ktorfit.Ktorfit
 import io.ktor.client.HttpClient
+import org.koin.core.qualifier.named
 import org.koin.dsl.module
 
 internal val httpClientModule =
@@ -25,4 +28,8 @@ internal val httpClientModule =
                 .httpClient(get<HttpClient>())
                 .build()
         }
+
+        single<HttpClient>(named("uploadClient")) { UploadHttpClientProvider.create() }
+
+        single { PresignedUploader(get(named("uploadClient"))) }
     }
diff --git a/core/network/src/main/java/com/twix/network/execute/UploadCall.kt b/core/network/src/main/java/com/twix/network/execute/UploadCall.kt
new file mode 100644
index 00000000..345b9c19
--- /dev/null
+++ b/core/network/src/main/java/com/twix/network/execute/UploadCall.kt
@@ -0,0 +1,37 @@
+package com.twix.network.execute
+
+import com.twix.result.AppError
+import com.twix.result.AppResult
+import io.ktor.client.plugins.ResponseException
+import io.ktor.client.statement.bodyAsText
+import kotlinx.io.IOException
+import kotlinx.serialization.SerializationException
+import java.net.SocketTimeoutException
+import kotlin.coroutines.cancellation.CancellationException
+
+suspend inline fun <T> safeUploadCall(crossinline call: suspend () -> T): AppResult<T> =
+    try {
+        AppResult.Success(call())
+    } catch (e: CancellationException) {
+        throw e
+    } catch (e: ResponseException) {
+        val status = e.response.status.value
+        val raw = runCatching { e.response.bodyAsText() }.getOrNull()
+
+        AppResult.Error(
+            AppError.Http(
+                status = status,
+                code = null,
+                message = null,
+                rawBody = raw,
+            ),
+        )
+    } catch (e: SocketTimeoutException) {
+        AppResult.Error(AppError.Timeout(e))
+    } catch (e: IOException) {
+        AppResult.Error(AppError.Network(e))
+    } catch (e: SerializationException) {
+        AppResult.Error(AppError.Serialization(e))
+    } catch (e: Throwable) {
+        AppResult.Error(AppError.Unknown(e))
+    }
diff --git a/core/network/src/main/java/com/twix/network/model/response/photo/mapper/PhotoMapper.kt b/core/network/src/main/java/com/twix/network/model/response/photo/mapper/PhotoMapper.kt
new file mode 100644
index 00000000..88d1d6d9
--- /dev/null
+++ b/core/network/src/main/java/com/twix/network/model/response/photo/mapper/PhotoMapper.kt
@@ -0,0 +1,10 @@
+package com.twix.network.model.response.photo.mapper
+
+import com.twix.domain.model.photo.PhotoLogUploadInfo
+import com.twix.network.model.response.photo.model.PhotoLogUploadUrlResponse
+
+fun PhotoLogUploadUrlResponse.toDomain(): PhotoLogUploadInfo =
+    PhotoLogUploadInfo(
+        uploadUrl = this.uploadUrl,
+        fileName = this.fileName,
+    )
diff --git a/core/network/src/main/java/com/twix/network/model/response/photo/model/PhotoLogUploadUrlResponse.kt b/core/network/src/main/java/com/twix/network/model/response/photo/model/PhotoLogUploadUrlResponse.kt
new file mode 100644
index 00000000..6c3763a7
--- /dev/null
+++ b/core/network/src/main/java/com/twix/network/model/response/photo/model/PhotoLogUploadUrlResponse.kt
@@ -0,0 +1,10 @@
+package com.twix.network.model.response.photo.model
+
+import kotlinx.serialization.SerialName
+import kotlinx.serialization.Serializable
+
+@Serializable
+data class PhotoLogUploadUrlResponse(
+    @SerialName("uploadUrl") val uploadUrl: String,
+    @SerialName("fileName") val fileName: String,
+)
diff --git a/core/network/src/main/java/com/twix/network/service/PhotoLogService.kt b/core/network/src/main/java/com/twix/network/service/PhotoLogService.kt
new file mode 100644
index 00000000..fbb2a5e3
--- /dev/null
+++ b/core/network/src/main/java/com/twix/network/service/PhotoLogService.kt
@@ -0,0 +1,12 @@
+package com.twix.network.service
+
+import com.twix.network.model.response.photo.model.PhotoLogUploadUrlResponse
+import de.jensklingenberg.ktorfit.http.GET
+import de.jensklingenberg.ktorfit.http.Query
+
+interface PhotoLogService {
+    @GET("api/v1/photologs/upload-url")
+    suspend fun getUploadUrl(
+        @Query("goalId") goalId: Long,
+    ): PhotoLogUploadUrlResponse
+}
diff --git a/core/network/src/main/java/com/twix/network/upload/PresignedUploader.kt b/core/network/src/main/java/com/twix/network/upload/PresignedUploader.kt
new file mode 100644
index 00000000..42d4690f
--- /dev/null
+++ b/core/network/src/main/java/com/twix/network/upload/PresignedUploader.kt
@@ -0,0 +1,31 @@
+package com.twix.network.upload
+
+import com.twix.network.execute.safeUploadCall
+import com.twix.result.AppResult
+import io.ktor.client.HttpClient
+import io.ktor.client.request.put
+import io.ktor.client.request.setBody
+import io.ktor.http.ContentType
+import io.ktor.http.contentType
+import io.ktor.http.isSuccess
+
+class PresignedUploader(
+    private val client: HttpClient,
+) {
+    suspend fun upload(
+        uploadUrl: String,
+        bytes: ByteArray,
+        contentType: String = "image/jpeg",
+    ): AppResult<Unit> =
+        safeUploadCall {
+            val response =
+                client.put(uploadUrl) {
+                    contentType(ContentType.parse(contentType))
+                    setBody(bytes)
+                }
+
+            if (!response.status.isSuccess()) {
+                throw IllegalStateException("S3 upload failed: ${response.status.value}")
+            }
+        }
+}
diff --git a/data/src/main/java/com/twix/data/di/RepositoryModule.kt b/data/src/main/java/com/twix/data/di/RepositoryModule.kt
index 6fb9e27c..feda5909 100644
--- a/data/src/main/java/com/twix/data/di/RepositoryModule.kt
+++ b/data/src/main/java/com/twix/data/di/RepositoryModule.kt
@@ -3,9 +3,11 @@ package com.twix.data.di
 import com.twix.data.repository.DefaultAuthRepository
 import com.twix.data.repository.DefaultGoalRepository
 import com.twix.data.repository.DefaultOnboardingRepository
+import com.twix.data.repository.DefaultPhotoLogRepository
 import com.twix.domain.repository.AuthRepository
 import com.twix.domain.repository.GoalRepository
 import com.twix.domain.repository.OnBoardingRepository
+import com.twix.domain.repository.PhotoLogRepository
 import org.koin.dsl.module
 
 internal val repositoryModule =
@@ -19,4 +21,7 @@ internal val repositoryModule =
         single<AuthRepository> {
             DefaultAuthRepository(get(), get())
         }
+        single<PhotoLogRepository> {
+            DefaultPhotoLogRepository(get(), get())
+        }
     }
diff --git a/data/src/main/java/com/twix/data/repository/DefaultPhotoLogRepository.kt b/data/src/main/java/com/twix/data/repository/DefaultPhotoLogRepository.kt
new file mode 100644
index 00000000..faafae5f
--- /dev/null
+++ b/data/src/main/java/com/twix/data/repository/DefaultPhotoLogRepository.kt
@@ -0,0 +1,42 @@
+package com.twix.data.repository
+
+import com.twix.domain.model.photo.PhotoLogUploadInfo
+import com.twix.domain.repository.PhotoLogRepository
+import com.twix.network.execute.safeApiCall
+import com.twix.network.model.response.photo.mapper.toDomain
+import com.twix.network.service.PhotoLogService
+import com.twix.network.upload.PresignedUploader
+import com.twix.result.AppResult
+
+class DefaultPhotoLogRepository(
+    private val service: PhotoLogService,
+    private val uploader: PresignedUploader,
+) : PhotoLogRepository {
+    override suspend fun getUploadUrl(goalId: Long): AppResult<PhotoLogUploadInfo> = safeApiCall { service.getUploadUrl(goalId).toDomain() }
+
+    override suspend fun uploadPhotoLogImage(
+        goalId: Long,
+        bytes: ByteArray,
+        contentType: String,
+    ): AppResult<String> {
+        // 서버에서 presigned url 발급
+        val infoResult = getUploadUrl(goalId)
+        val info =
+            when (infoResult) {
+                is AppResult.Success -> infoResult.data
+                is AppResult.Error -> return infoResult
+            }
+
+        // S3로 직접 업로드
+        val uploadResult =
+            uploader.upload(
+                uploadUrl = info.uploadUrl,
+                bytes = bytes,
+                contentType = contentType,
+            )
+        if (uploadResult is AppResult.Error) return uploadResult
+
+        // fileName을 key로 사용함. 인증샷 등록 API에서 사용
+        return AppResult.Success(info.fileName)
+    }
+}
diff --git a/domain/src/main/java/com/twix/domain/model/photo/PhotoLogUploadInfo.kt b/domain/src/main/java/com/twix/domain/model/photo/PhotoLogUploadInfo.kt
new file mode 100644
index 00000000..f0b90251
--- /dev/null
+++ b/domain/src/main/java/com/twix/domain/model/photo/PhotoLogUploadInfo.kt
@@ -0,0 +1,6 @@
+package com.twix.domain.model.photo
+
+data class PhotoLogUploadInfo(
+    val uploadUrl: String = "",
+    val fileName: String = "",
+)
diff --git a/domain/src/main/java/com/twix/domain/repository/PhotoLogRepository.kt b/domain/src/main/java/com/twix/domain/repository/PhotoLogRepository.kt
new file mode 100644
index 00000000..fc598301
--- /dev/null
+++ b/domain/src/main/java/com/twix/domain/repository/PhotoLogRepository.kt
@@ -0,0 +1,14 @@
+package com.twix.domain.repository
+
+import com.twix.domain.model.photo.PhotoLogUploadInfo
+import com.twix.result.AppResult
+
+interface PhotoLogRepository {
+    suspend fun getUploadUrl(goalId: Long): AppResult<PhotoLogUploadInfo>
+
+    suspend fun uploadPhotoLogImage(
+        goalId: Long,
+        bytes: ByteArray,
+        contentType: String,
+    ): AppResult<String>
+}